[Fork] PR list call to action

[outofambit]

this is a revisiting of #8936 and #8937

Description

• adds a version of the PR list that includes a link to view the current PR online if its in an upstream repo
• the hope is that if someone sees the PR badge on the branch dropdown and they open the PR list looking for their PR, they'll see this link as a path forward
• its also worth nothing this is likely a temporary design while we work towards redesigning the PR list (cc @ampinsk)

Screenshots

Release notes

Notes: [Added] Link in Pull Request list to view the current pull request on GitHub

Testing notes

1. Select a fork in desktop
2. Open a pull request from your current branch that targets the upstream repository (aka make a PR from a branch in outofambit/desktop to be merged into desktop/desktop)
3. See pr badge in branch dropdown button
4. Open branch list to PR tab and see new message

[ampinsk]

Thanks for working through this together @outofambit! ✨

[tierninho]

Possible to outline the repro steps for this? I attempted to recreate this but ran into some blockers as the following are assumed to be true:

• the user has to have no PRs open in the forked repo to see the new messaging
• all upstream PR badges remain hidden

However, in your screenshot, it shows a PR badge. Where did it come from?

[outofambit]

@tierninho i added steps to the PR description! hopefully that helps, lmk if you have more questions! (the pr badge in the branch dropdown is displayed if a matching pr is found in the fork or its upstream)

[tierninho]

Thanks for the steps. I can now see the link however it disappears and goes back to the original default state after clicking a variety of buttons, like the PR refresh button, fetch button, switch back/forth with branches tab.

From:

to:

The messaging returns if I go to another repo and return.

[tierninho]

Things seem to be working great now ✅ after the latest round of changes.

[kuychaco]

Thanks @outofambit 🚀. Thanks for the thorough testing @tierninho ✨

changes implemented