feat: M2TS (#2896)

Support the Blu-ray disc Audio-Video (BDAV) MPEG-2 Transport Stream (M2TS) format.

https://en.wikipedia.org/wiki/.m2ts

Fixes: #2350

mobile/lib/utils/files_helper.dart

@@ -137,6 +137,12 @@ class FileHelper {
       case 'jxl':
         return {"type": "image", "subType": "jxl"};
 
+      case 'mts':
+        return {"type": "video", "subType": "mp2t"};
+
+      case 'm2ts':
+        return {"type": "video", "subType": "mp2t"};
+
       default:
         return {"type": "unsupport", "subType": "unsupport"};
     }