[YouTube] Avatars, banners and subscriber count unavailable sometimes on channels

[killerrook]

Checklist

• I am able to reproduce the bug with the latest version given here: CLICK THIS LINK.
• I made sure that there are no existing issues - open or closed - which I could contribute my information to.
• I have read the FAQ and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one bug.
• I have read and understood the contribution guidelines.

Affected version

0.26.1

Steps to reproduce the bug

1. Open https://www.youtube.com/channel/UCxcrzzhQDj5zKJbXfIscCtg in newpipe
2. See subscriber count unavailable (refer to screenshot)

Expected behavior

Should fetch subsciber count

Actual behavior

It isn't able to fetch the aforesaid information.

Screenshots/Screen recordings

Logs

No response

Affected Android/Custom ROM version

One ui 6.0 android 14

Affected device model

Samsung s21 fe

Additional information

Most likely requires extractor changes.

[AudricV]

YouTube is A/B testing a new channel header for user channels, we partially support it currently (only for system channels such as the sports one where it was only returned before).

I already added support for it, and this change will be soon pushed and added in a future pull request of the extractor which will be linked to this issue.

[oifj34f34f]

Related: yt-dlp/yt-dlp#9893, iv-org/invidious#4681