Fix GitHub bot avatar URL

[tsutoringo]

Summary

• Fix GitHub avatar URL generation for bot noreply commit authors

• Fall back to the GitHub commit author API when the CDN email avatar endpoint cannot resolve bot noreply emails

• Add tests covering bot noreply and regular user noreply author emails

• Before
  

• After
  

Test Plan

• cargo test -p git_hosting_providers --features gpui/test-support

Self-Review Checklist:

• I've reviewed my own diff for quality, security, and reliability
• Unsafe blocks (if any) have justifying comments
• The content is consistent with the UI/UX checklist
• Tests cover the new/changed behavior
• Performance impact has been considered and is acceptable

Release Notes:

• Fixed GitHub avatar lookup for bot noreply commit authors.

[ChristopherBiscardi]

Heya! thanks for the PR.

What is the source for the url construction here? Is there a github docs link that indicates this is how the urls should be handled?

[tsutoringo]

Thanks for the review!
I couldn't find any official documentation for this endpoint as it was already being used this way before my changes.
e.g., https://avatars.githubusercontent.com/u/e?email={}&s=128
It seems to be a bit of a hacky workaround to avoid API limits, and it falls back to the API for bots.
Unfortunately, it doesn't seem to work correctly for bot emails.

Examples.
When using email:
https://avatars.githubusercontent.com/u/e?email=29139614+renovate[bot]@users.noreply.github.com&s=128

API called during fallback:
https://api.github.com/repos/zed-industries/zed/commits/bf185f7402dc7d0445f64d5d9af260f328af6eb9

Endpoint returned by the API called during fallback:
https://avatars.githubusercontent.com/in/2740?v=4

[ChristopherBiscardi]

Ok yeah I see. This does what it is supposed to here.