[Gloucestershire] Don’t allow anonymous reporting for City categories

[davea]

The Gloucestershire cobrand was allowing anonymous reports for Gloucester City categories, which should not be permitted since Gloucester's cobrand does not enable anonymous reporting.

For FD-6454

[skip changelog]

[codecov]

Codecov Report

❌ Patch coverage is 85.71429% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 82.63%. Comparing base (151c8cf) to head (0ac34c8).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
perllib/FixMyStreet/Cobrand/Gloucestershire.pm	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5794      +/-   ##
==========================================
- Coverage   82.64%   82.63%   -0.02%     
==========================================
  Files         457      457              
  Lines       35716    35722       +6     
  Branches     5822     5825       +3     
==========================================
+ Hits        29519    29520       +1     
- Misses       4501     4505       +4     
- Partials     1696     1697       +1     

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[dracos]

Is okay, but as discussed after checking it perhaps it is easier to remove the allow_anonymous_reports function here and set the admin tickboxes instead, then that works without needing special behaviour.

[dracos]

This function is the same as Default's now, apart from it doesn't have the anonymous_allowed check. So perhaps here instead we could remove this function entirely and tick every category for Gloucestershire to have the same effect without special code?