fix(server): select main stream according to bitrate (#18375)

* fix main stream

* update unit tests

---------

Co-authored-by: mertalev <101130780+mertalev@users.noreply.github.com>

server/src/repositories/media.repository.ts

@@ -209,7 +209,7 @@ export class MediaRepository {
           index: stream.index,
           codecType: stream.codec_type,
           codecName: stream.codec_name,
-          frameCount: this.parseInt(options?.countFrames ? stream.nb_read_packets : stream.nb_frames),
+          bitrate: this.parseInt(stream.bit_rate),
         })),
     };
   }