MediaViewerView: move TopBar to Scaffold topbar

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/viewer/MediaViewerView.kt

@@ -121,19 +121,8 @@ fun MediaViewerView(
     Scaffold(
         modifier,
         containerColor = Color.Transparent,
-        snackbarHost = { SnackbarHost(snackbarHostState) },
+        topBar = {
-    ) {
-        val pagerState = rememberPagerState(state.currentIndex, 0f) {
-            state.listData.size
-        }
-        LaunchedEffect(pagerState) {
-            snapshotFlow { pagerState.currentPage }.collect { page ->
-                state.eventSink(MediaViewerEvent.OnNavigateTo(page))
-            }
-        }
-        // Top bar
             AnimatedVisibility(
-            modifier = Modifier.zIndex(1f),
                 visible = showOverlay,
                 enter = fadeIn(),
                 exit = fadeOut(),
@@ -177,6 +166,17 @@ fun MediaViewerView(
                     }
                 }
             }
+        },
+        snackbarHost = { SnackbarHost(snackbarHostState) },
+    ) {
+        val pagerState = rememberPagerState(state.currentIndex, 0f) {
+            state.listData.size
+        }
+        LaunchedEffect(pagerState) {
+            snapshotFlow { pagerState.currentPage }.collect { page ->
+                state.eventSink(MediaViewerEvent.OnNavigateTo(page))
+            }
+        }
         HorizontalPager(
             state = pagerState,
             modifier = Modifier,