Feat: Support for UserFeedback

[ueman]

📜 Description

Adds support for user feedback.
Builds on #505 and thus should be merged after it.

💡 Motivation and Context

Closes #215

💚 How did you test it?

📝 Checklist

• I reviewed submitted code
• I added tests to verify changes
• I updated the docs if needed
• All tests passing
• No breaking changes

🔮 Next steps

[codecov-commenter]

Codecov Report

❌ Patch coverage is 71.15385% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.32%. Comparing base (828de72) to head (cb459f4).
⚠️ Report is 1801 commits behind head on main.

Files with missing lines	Patch %	Lines
dart/lib/src/sentry_envelope_item.dart	50.00%	4 Missing ⚠️
dart/lib/src/sentry_user_feedback.dart	80.00%	4 Missing ⚠️
dart/lib/src/hub_adapter.dart	33.33%	2 Missing ⚠️
dart/lib/src/noop_hub.dart	0.00%	2 Missing ⚠️
dart/lib/src/sentry.dart	0.00%	2 Missing ⚠️
dart/lib/src/hub.dart	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #506      +/-   ##
==========================================
- Coverage   91.77%   91.32%   -0.45%     
==========================================
  Files          73       74       +1     
  Lines        2371     2422      +51     
==========================================
+ Hits         2176     2212      +36     
- Misses        195      210      +15     

☔ View full report in Codecov by Sentry.
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[marandaneto]

What tests do we want to have for the UI, if the UI is wanted at all? Do we want to have widget and golden image tests?

we actually don't need a UI at all, but its nice that you have added to the sample, so we can keep it.

spec is here https://develop.sentry.dev/sdk/features/#user-feedback
we can tackle #441 later as its not a blocker and it'd require changes on native SDKs too probably.

[marandaneto]

this PR branches from feat/attachments, I'd not get blocked by this though because user feedback and attachments are different features that could be used together, but don't depend on each other.

overall nice PR, unit tests and so on are missing but I like where this is going :) thanks @ueman

[philipphofmann]

API looks good. Didn't check the dart details, though.

[ueman]

The UI is in the example app for now. I do intend to clean it up and write tests for it in a follow-up PR.

[marandaneto]

@ueman is it ready for final code review? @bruno-garcia or @philipphofmann will do it, thanks

[ueman]

@ueman is it ready for final code review? @bruno-garcia or @philipphofmann will do it, thanks

Yep, it's ready now.

[bruno-garcia]

LGTM

[marandaneto]

LGTM