Add feedbackLink to experiment

[EdmondChuiHW]

Summary

Minor tweaks to help dogfooders read docs and send feedback.

• add feedbackLink to experiment
• allow dynamic feedbackLink from globalThis for alternative URLs such as FB internal feedback form
• show feedbackLink from RN Welcome panel

Stack

• This is part of a stack.
• Depends on: Add doclink to experiment #31
• Blocks: Add "[FB-only] Send feedback" button #33
• Preview this PR when base branches are merged: add feedback link support EdmondChuiHW/rn-chrome-devtools-frontend2#4
• Relevant internal diff: https://www.internalfb.com/diff/D55352292

Test plan

With globalThis.reactNativeFeedbackLink = 'https://example.com':

Upstreaming plan

• This commit should be sent as a patch to the upstream devtools-frontend repo. I've reviewed the contribution guide.
• This commit is React Native-specific and cannot be upstreamed.

[huntie]

Unlike the previous PR, I don't think we should implement this link — motivation being that we won't provide this for OSS (unless perhaps we'd want to give Expo the hook to do so).

Let's double-down on the Bugnub in your next PR as the only (optionally set) CTA for feedback.

[EdmondChuiHW]

Ah I should have been more clear in the summary about this feedback link being optional.

In other words, landing this PR is no-op for open-source. The feedback link has no default if the global var isn't set. And thus the link in the welcome screen would not be shown if it's not present.

Bottom line: without the globalThis.reactNativeFeedbackLink = 'https://example.com' equivalent from our internal embedder script, this PR is no-op.

I initially thought about using custom labels, e.g. [FB-only] Send feedback, if we have an appetite for another global var (and making it work with i18n in CDT).

Or we can also prepend an unstable_ prefix to the global vars if we want to signal this to OSS (and hardcode the label to read [FB-only] Send feedback)

Happy to adjust if there's a preference to hide this all together in the experiment or RN Welcome page. While the toolbar button in the next PR is present across all panels, showing doc and feedback links together seems like a CDT UI pattern (and makes sense to me too)

[EdmondChuiHW]

Discussed offline. No diff for settings or RNWelcome. Closing PR