metrics(feedback): Track source emitted by SDK fxs

[aliu39]

This is a useful property we're not tracking in metrics -- right now we assume all NEW_FEEDBACK_ENVELOPE's are from the widget, but they could be sent by the SDK too.

Code refs: https://github.com/getsentry/sentry-javascript/blob/d651f1319c95867be03c55f95c5878771c1e4c26/packages/feedback/src/constants/index.ts#L26 https://github.com/getsentry/sentry-javascript/blob/d651f1319c95867be03c55f95c5878771c1e4c26/packages/feedback/src/modal/components/Form.tsx#L124

[aliu39]

Unsure about naming - could be client_type, client_source_type..

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 77.92%. Comparing base (60c3965) to head (9b80f00).

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #70810      +/-   ##
==========================================
+ Coverage   69.05%   77.92%   +8.86%     
==========================================
  Files        6573     6573              
  Lines      292834   292783      -51     
  Branches    50542    50531      -11     
==========================================
+ Hits       202220   228140   +25920     
+ Misses      83892    58395   -25497     
+ Partials     6722     6248     -474     

Files	Coverage Δ
src/sentry/feedback/usecases/create_feedback.py	86.54% <ø> (ø)

... and 1429 files with indirect coverage changes

[getsantry[bot]]

This pull request has gone three weeks without activity. In another week, I will close it.

But! If you comment or otherwise update it, I will reset the clock, and if you add the label WIP, I will leave it alone unless WIP is removed ... forever!

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"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀