[bug] Discover UI stuck on searching after deleting index pattern (#8659)

* [bug] Discover UI stuck on searching after deleting index pattern

When using Discover with query enhancement enabled, deleting an index pattern from Index Management does not properly update the "Recently selected data" list in Discover. This causes the UI to become stuck in a "Searching" state when attempting to use
Discover after deleting an index pattern.

Handle the error case where the use index patterns hook caught error when
enhancements was enabled.

issue resolved:
#8612

Signed-off-by: Kawika Avilla <[email protected]>

* Changeset file for PR #8659 created/updated

---------

Signed-off-by: Kawika Avilla <[email protected]>
Co-authored-by: opensearch-changeset-bot[bot] <154024398+opensearch-changeset-bot[bot]@users.noreply.github.com>

Author: kavilla

changelogs/fragments/8659.yml

@@ -0,0 +1,2 @@
+fix:
+- Discover UI stuck on searching after failing to find deleted index pattern ([#8659](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/8659))

src/plugins/discover/public/application/view_components/utils/use_index_pattern.ts

@@ -74,25 +74,25 @@ export const useIndexPattern = (services: DiscoverViewServices) => {
             handleIndexPattern();
           }
         } else {
-          try {
-            const ip = await fetchIndexPatternDetails(indexPatternIdFromState);
-            if (isMounted) {
-              setIndexPattern(ip);
-            }
-          } catch (error) {
-            if (isMounted) {
-              const warningMessage = i18n.translate('discover.indexPatternFetchErrorWarning', {
-                defaultMessage: 'Error fetching index pattern: {error}',
-                values: { error: (error as Error).message },
-              });
-              toastNotifications.addWarning(warningMessage);
-            }
+          const ip = await fetchIndexPatternDetails(indexPatternIdFromState);
+          if (isMounted) {
+            setIndexPattern(ip);
           }
         }
       }
     };
 
-    handleIndexPattern();
+    try {
+      handleIndexPattern();
+    } catch (error) {
+      if (isMounted) {
+        const warningMessage = i18n.translate('discover.indexPatternFetchErrorWarning', {
+          defaultMessage: 'Error fetching index pattern: {error}',
+          values: { error: (error as Error).message },
+        });
+        toastNotifications.addWarning(warningMessage);
+      }
+    }
 
     return () => {
       isMounted = false;