Fix multiple memory leaks in Region::process() function (flameshot-org#4284)

* Fix multiple memory leaks in Region::process() function

- Add proper cleanup for allocated QApplication object
- Add proper cleanup for allocated char** argv array
- Add proper cleanup for allocated int* argc pointer
- Ensure all return paths properly clean up allocated memory
- Prevents memory leaks when Region::process() is called

Fixes multiple memory leaks identified in codebase analysis.

* Apply clang-format to fix code style compliance

- Remove trailing whitespace
- Normalize line endings
- Ensure compliance with project's clang-format rules

Fixes CI test-clang-format workflow failure.

* Refactor cleanup logic in Region::process

Introduced a cleanup lambda to handle memory deallocation in Region::process, replacing repeated code with a single reusable function for better maintainability and readability.

* Format cleanup lambda for readability

Reformatted the cleanup lambda in Region::process for improved readability by expanding it to multiple lines.

* Refactor Region::process to use smart pointers

Replaces manual memory management with std::unique_ptr for temporary QApplication and argument variables. Removes redundant cleanup logic for improved safety and readability.

Author: avineet4

src/utils/valuehandler.cpp

@@ -10,6 +10,7 @@
 #include <QRegularExpression>
 #include <QStandardPaths>
 #include <QVariant>
+#include <memory>
 
 // VALUE HANDLER
 
@@ -530,10 +531,11 @@ bool Region::check(const QVariant& val)
 QVariant Region::process(const QVariant& val)
 {
     // FIXME: This is temporary, just before D-Bus is removed
-    char** argv = new char*[1];
-    int* argc = new int{ 0 };
+    auto argv = std::make_unique<char*[]>(1);
+    auto argc = std::make_unique<int>(0);
+    std::unique_ptr<QApplication> tempApp;
     if (QGuiApplication::screens().empty()) {
-        new QApplication(*argc, argv);
+        tempApp = std::make_unique<QApplication>(*argc, argv.get());
     }
 
     QString str = val.toString();