feature(mobile): Hardening synchronization mechanism + Pull to refresh (#2085)

* fix(mobile): allow syncing duplicate local IDs

* enable to run isar unit tests on CI

* serialize sync operations, add pull to refresh on timeline

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Co-authored-by: Fynn Petersen-Frey <zoodyy@users.noreply.github.com>

mobile/test/asset_grid_data_structure_test.dart

@@ -20,6 +20,7 @@ void main() {
         fileModifiedAt: date,
         updatedAt: date,
         durationInSeconds: 0,
+        type: AssetType.image,
         fileName: '',
         isFavorite: false,
         isLocal: false,