Figure out a way to allow guest downloads of PR APKs

[opusforlife2]

Checklist

• I checked, but didn't find any duplicates (open OR closed) of this issue in the repo.
• I have read the contribution guidelines given at https://github.com/TeamNewPipe/NewPipe/blob/HEAD/.github/CONTRIBUTING.md.
• This issue contains only one feature request. I will open one issue for every feature I want to request.

Describe the feature you want

There should be a way for guest users (those who aren't logged in to Github) to download test APKs from PRs.

Is your feature request related to a problem? Please describe it

Unlike commenting on issues and PRs, making the user sign in before downloading a test APK doesn't make sense. Some guest users might even be discouraged from testing PRs because they do not want to make a Github account just for that one APK.

Additional context

#5539 was an effort in this direction. It is still a possible solution.

How will you/everyone benefit from this feature?

Less headache when testing PRs.

@TheAssassin I totally forgot about this second problem while opening that first issue.

[opusforlife2]

Any updates to Github that let us proceed forward here?