feat(mobile): upload image assets before videos (immich-app#3872)

* feat(mobile): upload image assets before videos

* mobile: sort by creation date before uploading assets

mobile/lib/modules/backup/services/backup.service.dart

@@ -218,7 +218,18 @@ class BackupService {
     bool anyErrors = false;
     final List<String> duplicatedAssetIds = [];
 
-    for (var entity in assetList) {
+    // Upload images before video assets
+    // these are further sorted by using their creation date so the upload goes as follows
+    // older images -> latest images -> older videos -> latest videos
+    List<AssetEntity> sortedAssets = assetList.sorted(
+      (a, b) {
+        final cmp = a.typeInt - b.typeInt;
+        if (cmp != 0) return cmp;
+        return a.createDateTime.compareTo(b.createDateTime);
+      },
+    );
+
+    for (var entity in sortedAssets) {
       try {
         if (entity.type == AssetType.video) {
           file = await entity.originFile;
@@ -248,7 +259,8 @@ class BackupService {
 
           req.fields['deviceAssetId'] = entity.id;
           req.fields['deviceId'] = deviceId;
-          req.fields['fileCreatedAt'] = entity.createDateTime.toUtc().toIso8601String();
+          req.fields['fileCreatedAt'] =
+              entity.createDateTime.toUtc().toIso8601String();
           req.fields['fileModifiedAt'] =
               entity.modifiedDateTime.toUtc().toIso8601String();
           req.fields['isFavorite'] = entity.isFavorite.toString();