CONFIG: Update DEVELOPER_DIR in GH Actions to Xcode 16

[adamayoung]

No description provided.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.40%. Comparing base (6e1fb3a) to head (a544ef4).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #211   +/-   ##
=======================================
  Coverage   89.40%   89.40%           
=======================================
  Files         204      204           
  Lines        2860     2860           
=======================================
  Hits         2557     2557           
  Misses        303      303           

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