Add background to loading state

libraries/mediaviewer/impl/src/main/kotlin/io/element/android/libraries/mediaviewer/impl/gallery/MediaGalleryView.kt

@@ -460,6 +460,10 @@ private fun EmptyContent(
 private fun LoadingContent(
     mode: MediaGalleryMode,
 ) {
+    Box(
+        modifier = Modifier.fillMaxSize(),
+    ) {
+        OnboardingBackground()
         Column(
             modifier = Modifier
                 .fillMaxSize()
@@ -478,6 +482,7 @@ private fun LoadingContent(
                 modifier = Modifier.align(Alignment.CenterHorizontally),
             )
         }
+    }
 }
 
 @PreviewsDayNight