[native] Fix video in VideoPlaybackModal displayed incorrectly

Summary:
https://linear.app/comm/issue/ENG-10078/invalid-video-size-in-videoplaybackmodal-on-android
The screenshot and explanation is included in linear ticket above. Adding `resizeMode` fixed the issue.

Test Plan: Display some videos in `VideoPlaybackModal` on iOS and Android.

Reviewers: bartek, tomek, ashoat

Reviewed By: ashoat

Subscribers: ashoat

Differential Revision: https://phab.comm.dev/D14191

native/media/video-playback-modal.react.js

@@ -725,6 +725,7 @@ function VideoPlaybackModal(props: Props): React.Node {
         onProgress={progressCallback}
         onEnd={resetVideo}
         onReadyForDisplay={readyForDisplayCallback}
+        resizeMode="contain"
       />
     );
   }