[GA 4 web] - handling when domain is an empty string

[joe-ayoub-segment]

Minor change from ?? to || for optional domain field in GA 4 web.

Testing

Tested locally and in stage

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 32.57%. Comparing base (41a9de1) to head (c2c4390).
⚠️ Report is 9 commits behind head on main.

❌ Your project status has failed because the head coverage (32.57%) is below the target coverage (70.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #3333       +/-   ##
===========================================
- Coverage   80.32%   32.57%   -47.75%     
===========================================
  Files        1257       14     -1243     
  Lines       25159      703    -24456     
  Branches     5217      119     -5098     
===========================================
- Hits        20208      229    -19979     
+ Misses       4163      474     -3689     
+ Partials      788        0      -788     

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