[Shared Element Transition] Fix exiting animations on Android (softwa…

…re-mansion#4038)

## Summary

I shouldn't clear the layout animation config when the shared element
transition doesn't start. Without this check, the exiting layout
animation couldn't start because LayoutAnimationManager doesn't contain
the view config.

## Test plan

Run exiting layout animation on Android.

android/src/main/java/com/swmansion/reanimated/layoutReanimation/SharedTransitionManager.java

@@ -49,15 +49,18 @@ protected View getTransitioningView(int tag) {
   }
 
   protected void viewsDidLayout() {
-    startSharedTransitionForViews(mAddedSharedViews, true);
+    tryStartSharedTransitionForViews(mAddedSharedViews, true);
     mAddedSharedViews.clear();
   }
 
   protected void onViewsRemoval(int[] tagsToDelete) {
     if (tagsToDelete != null) {
       visitTreeForTags(tagsToDelete, new SnapshotTreeVisitor());
 
-      startSharedTransitionForViews(mRemovedSharedViews, false);
+      boolean animationStarted = tryStartSharedTransitionForViews(mRemovedSharedViews, false);
+      if (!animationStarted) {
+        return;
+      }
       ConfigCleanerTreeVisitor configCleanerTreeVisitor = new ConfigCleanerTreeVisitor();
       for (View removedSharedView : mRemovedSharedViews) {
         visitTree(removedSharedView, configCleanerTreeVisitor);
@@ -85,19 +88,21 @@ protected void setNativeMethods(NativeMethodsHolder nativeMethods) {
     mNativeMethodsHolder = nativeMethods;
   }
 
-  private void startSharedTransitionForViews(List<View> sharedViews, boolean withNewElements) {
+  private boolean tryStartSharedTransitionForViews(
+      List<View> sharedViews, boolean withNewElements) {
     if (sharedViews.isEmpty()) {
-      return;
+      return false;
     }
     sortViewsByTags(sharedViews);
     List<SharedElement> sharedElements =
         getSharedElementsForCurrentTransition(sharedViews, withNewElements);
     if (sharedElements.isEmpty()) {
-      return;
+      return false;
     }
     setupTransitionContainer();
     reparentSharedViewsForCurrentTransition(sharedElements);
     startSharedTransition(sharedElements);
+    return true;
   }
 
   private void sortViewsByTags(List<View> views) {

ios/LayoutReanimation/REASharedTransitionManager.m

@@ -360,8 +360,8 @@ - (void)runSharedTransitionForSharedViewsOnScreen:(UIView *)screen
     }
     return false;
   });
-  BOOL startedAnimation = [self configureAndStartSharedTransitionForViews:removedViews];
-  if (startedAnimation) {
+  BOOL animationStarted = [self configureAndStartSharedTransitionForViews:removedViews];
+  if (animationStarted) {
     for (UIView *view in removedViews) {
       [_animationManager clearAnimationConfigForTag:view.reactTag];
     }