fix(preprod): Handle missing date_built in UI and backend (EME-671)

[runningcode]

Frontend: Update the build details sidebar to display a timestamp even when
date_built is not available by falling back to date_added. The tooltip now
shows "App build time" when displaying date_built, or "App upload time" when
displaying date_added.

Backend: Extract build_date from apple_app_info and set it as date_built.
Previously, Launchpad was sending build_date in apple_app_info, but the Sentry
endpoint was not extracting it. This fix ensures that the build date from the
XCArchive metadata is properly stored in the date_built field.

Before:

After:

This ensures users always see a relevant timestamp for their builds.

[linear]

EME-671 handle no date_built in UI

[github-actions]

🚨 Warning: This pull request contains Frontend and Backend changes!

It's discouraged to make changes to Sentry's Frontend and Backend in a single pull request. The Frontend and Backend are not atomically deployed. If the changes are interdependent of each other, they must be separated into two pull requests and be made forward or backwards compatible, such that the Backend or Frontend can be safely deployed independently.

Have questions? Please ask in the #discuss-dev-infra channel.

[codecov]

Codecov Report

❌ Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...d/api/endpoints/project_preprod_artifact_update.py	33.33%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #104444      +/-   ##
===========================================
+ Coverage   80.19%    80.52%   +0.32%     
===========================================
  Files        9345      9345              
  Lines      400021    400025       +4     
  Branches    25651     25651              
===========================================
+ Hits       320809    322118    +1309     
+ Misses      78763     77458    -1305     
  Partials      449       449