[iOS]update isMocked documentation

[TimHoogstrate]

Resolves: 1216

Pre-launch Checklist

• I made sure the project builds.
• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or this PR is does not need version changes.
• I updated CHANGELOG.md to add a description of the change.
• I updated/added relevant documentation (doc comments with ///).
• I rebased onto main.
• I added new tests to check the change I am making, or this PR does not need tests.
• I made sure all existing and new tests are passing.
• I ran dart format . and committed any changes.
• I ran flutter analyze and fixed any errors.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (5b07c28) to head (ccafe08).
Report is 81 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #1370   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           13        13           
  Lines          244       244           
=========================================
  Hits           244       244           

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[OmarLajam]

This should be merged to update the documentation of isMocked on iOS 15+. The current documentation is misleading.