Fix Part of #277 : Added UrlImage Loading Tests (#5681)

**Explanation:**
Fix part of #277 by introducing a set of test cases to verify the
functionality of image loading via the `UrlImageParser` class using the
`GlideImageLoader`. The tests ensure that images (including PNG, SVG,
and SVGZ formats) are correctly loaded from URLs and that math drawables
(e.g., inline LaTeX) are rendered as expected. It covers scenarios for:
- Loading images from URLs of different formats (PNG, SVG, SVGZ).
- Verifying the behavior when loading multiple images at once.
- Ensuring that the image loading process finishes properly using Glide.

**Fixes:**
- This PR addresses the pending test cases for loading images from URLs
(as mentioned in issue #277) and resolves the related testing block.

## Essential Checklist
- [x] The PR title and explanation each start with "Fix #bugnum: " (If
this PR fixes part of an issue, prefix the title with "Fix part of
#bugnum: ...".)
- [ ] Any changes to
[scripts/assets](https://github.com/oppia/oppia-android/tree/develop/scripts/assets)
files have their rationale included in the PR explanation.
- [x] The PR follows the [style
guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android
Studio
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#undo-unnecessary-changes)).
- [x] The PR is made from a branch that's **not** called "develop" and
is up-to-date with "develop".
- [x] The PR is **assigned** to the appropriate reviewers
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#clarification-regarding-assignees-and-reviewers-section)).

**All Tests Passed:**

![Image](https://github.com/user-attachments/assets/df5c4015-1583-4faf-8f98-3d361c2b5bbc)

Author: TanishMoral11

utility/src/test/java/org/oppia/android/util/parser/image/UrlImageParserTest.kt

@@ -2,6 +2,7 @@ package org.oppia.android.util.parser.image
 
 import android.app.Application
 import android.content.Context
+import android.os.Looper
 import android.widget.TextView
 import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
@@ -26,6 +27,7 @@ import org.oppia.android.util.locale.LocaleProdModule
 import org.oppia.android.util.logging.LoggerModule
 import org.oppia.android.util.parser.html.CustomHtmlContentHandler.ImageRetriever.Type.BLOCK_IMAGE
 import org.oppia.android.util.parser.html.CustomHtmlContentHandler.ImageRetriever.Type.INLINE_TEXT_IMAGE
+import org.robolectric.Shadows
 import org.robolectric.annotation.LooperMode
 import javax.inject.Inject
 import javax.inject.Singleton
@@ -79,6 +81,79 @@ class UrlImageParserTest {
     assertThat(loadedBitmaps.first()).contains("test_image.svg")
   }
 
+  @Test
+  fun testLoadDrawable_bitmapFromUrl_loadsBlockImage() {
+    val imageUrl = "https://example.com/test_image.png"
+    urlImageParser.loadDrawable(imageUrl, BLOCK_IMAGE)
+
+    val loadedBitmaps = testGlideImageLoader.getLoadedBitmaps()
+    assertThat(loadedBitmaps).hasSize(1)
+    assertThat(loadedBitmaps.first()).contains("test_image.png")
+  }
+
+  @Test
+  fun testLoadDrawable_svgFromUrlBlockType_loadsBlockSvgImage() {
+    val imageUrl = "https://example.com/test_image.svg"
+    urlImageParser.loadDrawable(imageUrl, BLOCK_IMAGE)
+
+    Shadows.shadowOf(Looper.getMainLooper()).idle()
+
+    val loadedSvgs = testGlideImageLoader.getLoadedBlockSvgs()
+    assertThat(loadedSvgs).hasSize(1)
+    assertThat(loadedSvgs.first()).contains("test_image.svg")
+  }
+
+  @Test
+  fun testLoadDrawable_svgzFromUrlBlockType_loadsBlockSvgImage() {
+    val imageUrl = "https://example.com/test_image.svgz"
+    urlImageParser.loadDrawable(imageUrl, BLOCK_IMAGE)
+
+    Shadows.shadowOf(Looper.getMainLooper()).idle()
+
+    val loadedSvgs = testGlideImageLoader.getLoadedBlockSvgs()
+    assertThat(loadedSvgs).hasSize(1)
+    assertThat(loadedSvgs.first()).contains("test_image.svgz")
+  }
+
+  @Test
+  fun testLoadMathDrawable_latexInlineType_loadsInlineLatexImage() {
+    val rawLatex = "\\frac{2}{6}"
+    urlImageParser.loadMathDrawable(
+      rawLatex = rawLatex,
+      lineHeight = 20f,
+      type = INLINE_TEXT_IMAGE
+    )
+
+    Shadows.shadowOf(Looper.getMainLooper()).idle()
+
+    val loadedMathDrawables = testGlideImageLoader.getLoadedMathDrawables()
+    assertThat(loadedMathDrawables).hasSize(1)
+    assertThat(loadedMathDrawables.first().rawLatex).isEqualTo("\\frac{2}{6}")
+    assertThat(loadedMathDrawables.first().useInlineRendering).isTrue()
+  }
+
+  @Test
+  fun testLoadDrawable_multipleImages_loadsAllImages() {
+    val imageUrl1 = "https://example.com/test_image1.png"
+    val imageUrl2 = "https://example.com/test_image2.svg"
+    val imageUrl3 = "https://example.com/test_image3.svgz"
+
+    urlImageParser.loadDrawable(imageUrl1, BLOCK_IMAGE)
+    urlImageParser.loadDrawable(imageUrl2, BLOCK_IMAGE)
+    urlImageParser.loadDrawable(imageUrl3, BLOCK_IMAGE)
+
+    Shadows.shadowOf(Looper.getMainLooper()).idle()
+
+    val loadedBitmaps = testGlideImageLoader.getLoadedBitmaps()
+    val loadedBlockSvgs = testGlideImageLoader.getLoadedBlockSvgs()
+
+    assertThat(loadedBitmaps).hasSize(1)
+    assertThat(loadedBlockSvgs).hasSize(2)
+    assertThat(loadedBitmaps.first()).contains("test_image1.png")
+    assertThat(loadedBlockSvgs.first()).contains("test_image2.svg")
+    assertThat(loadedBlockSvgs[1]).contains("test_image3.svgz")
+  }
+
   @Test
   fun testGetDrawable_svgz_loadsSvgzBlockImage() {
     urlImageParser.getDrawable("test_image.svgz")