set `MediaStreamTrack enbaled = false` cause Aplication crash in iOS Safari 15.1

[yuki uchida]

# Overview
When using WebRTC connection, MediaStreaemTrack(video) enabled option cause application crash

## steps to reproduce
device A: iOS Safari
device B: Any(ChromeM101 on Mac and iPadOS(unknown version) was tested)

1. (device A&B) visit https://yasubaba.github.io/prodSkyWay/room_videoMute/
2. (device A&B) Accept permissions for camera and microphone.
3. join Room and start WebRTC Connection.
4. (device A) click `Video Mute/Unmute` 
5 (device A) iOS Safari crashed.


The mute procedure is very simple as follows
```
document.getElementById('js-videoEnabled').addEventListener('click', () => {
  localStream.getVideoTracks().forEach( track => {
    track.enabled = !track.enabled;
  });
})
```


## Actual Results
iOS Safari always crash.

## Expected Results
No error occurs.

## Hardware
iPhone12 iOS15.1


I prepared safari crash log, but i don't know how to share with you.
I can prepare google Drive URL, but I am not sure if it is okay to keep the crash log in a publicly visible location.
If you need crash log, please tell me how to share.

[youenn fablet]

This should be fixed in iOS 15.3 and above.