Reset feature flag service after test

Author: RafaelKayumov

WooCommerce/WooCommerceTests/Tools/DefaultImageServiceTests.swift

@@ -268,9 +268,16 @@ final class DefaultImageServiceTests: XCTestCase {
 
     func testDownloadAndCacheImageForImageView_withEmptyBounds_usesDefaultThumbnailSize() {
         // Given
-        let featureFlagService = MockFeatureFlagService()
-        featureFlagService.isProductImageOptimizedHandlingEnabled = true
-        ServiceLocator.setFeatureFlagService(featureFlagService)
+        let originalFeatureFlagService = ServiceLocator.featureFlagService
+        defer {
+            ServiceLocator.setFeatureFlagService(originalFeatureFlagService)
+        }
+
+        ServiceLocator.setFeatureFlagService(
+            MockFeatureFlagService(
+                isProductImageOptimizedHandlingEnabled: true
+            )
+        )
 
         let mockImageView = UIImageView(frame: .zero)
         let mockCache = MockImageCache(name: "Testing")