perf(mobile): remove load of thumbnails in the image provider (#17773)

Remove loading of thumbnail in the image provider

* Removed the load of the thumbnail from the local and remote image provider as they shall provide the image, not the thumbnail. The thumbnail gets provided by the thumbnail provider.
* The thumbnail provider is used as the loadingBuilder and the image provider as the imageProvider. Therefore loading the thumbnail in the image provider loads it a second time which is completely redundant, uses precious time and yields no results.

Co-authored-by: Alex <alex.tran1502@gmail.com>

mobile/lib/providers/image/immich_remote_image_provider.dart

@@ -57,12 +57,6 @@ class ImmichRemoteImageProvider
         AppSettingsEnum.loadOriginal.defaultValue,
       );
 
-  /// Whether to load the preview thumbnail first or not
-  bool get _loadPreview => Store.get(
-        AppSettingsEnum.loadPreview.storeKey,
-        AppSettingsEnum.loadPreview.defaultValue,
-      );
-
   // Streams in each stage of the image as we ask for it
   Stream<ui.Codec> _codec(
     ImmichRemoteImageProvider key,
@@ -70,21 +64,6 @@ class ImmichRemoteImageProvider
     ImageDecoderCallback decode,
     StreamController<ImageChunkEvent> chunkEvents,
   ) async* {
-    // Load a preview to the chunk events
-    if (_loadPreview) {
-      final preview = getThumbnailUrlForRemoteId(
-        key.assetId,
-        type: api.AssetMediaSize.thumbnail,
-      );
-
-      yield await ImageLoader.loadImageFromCache(
-        preview,
-        cache: cache,
-        decode: decode,
-        chunkEvents: chunkEvents,
-      );
-    }
-
     // Load the higher resolution version of the image
     final url = getThumbnailUrlForRemoteId(
       key.assetId,