fix(mobile): ensure current asset is set in asset viewer (#21504)

mobile/lib/presentation/widgets/asset_viewer/asset_viewer.state.dart

@@ -75,14 +75,23 @@ class AssetViewerStateNotifier extends AutoDisposeNotifier<AssetViewerState> {
   }
 
   void setAsset(BaseAsset? asset) {
+    if (asset == state.currentAsset) {
+      return;
+    }
     state = state.copyWith(currentAsset: asset, stackIndex: 0);
   }
 
   void setOpacity(int opacity) {
+    if (opacity == state.backgroundOpacity) {
+      return;
+    }
     state = state.copyWith(backgroundOpacity: opacity, showingControls: opacity == 255 ? true : state.showingControls);
   }
 
   void setBottomSheet(bool showing) {
+    if (showing == state.showingBottomSheet) {
+      return;
+    }
     state = state.copyWith(showingBottomSheet: showing, showingControls: showing ? true : state.showingControls);
     if (showing) {
       ref.read(videoPlayerControlsProvider.notifier).pause();
@@ -90,6 +99,9 @@ class AssetViewerStateNotifier extends AutoDisposeNotifier<AssetViewerState> {
   }
 
   void setControls(bool isShowing) {
+    if (isShowing == state.showingControls) {
+      return;
+    }
     state = state.copyWith(showingControls: isShowing);
   }
 
@@ -98,6 +110,9 @@ class AssetViewerStateNotifier extends AutoDisposeNotifier<AssetViewerState> {
   }
 
   void setStackIndex(int index) {
+    if (index == state.stackIndex) {
+      return;
+    }
     state = state.copyWith(stackIndex: index);
   }
 }