Do not allow anonymous contact forms

[itsisak]

Description

Removes the option to send contact forms anonymously

Testing

• The code quality is at a minimum required level of quality, readability, and performance.
• I have thoroughly tested my changes.

Updated the tests to match this new behavior

Related frontend pr: webkom/lego-webapp#5703

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.00%. Comparing base (0a65e5e) to head (bfdc3c7).
⚠️ Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3842      +/-   ##
==========================================
- Coverage   90.01%   90.00%   -0.01%     
==========================================
  Files         765      765              
  Lines       24503    24480      -23     
==========================================
- Hits        22056    22033      -23     
  Misses       2447     2447              

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[falbru]

LGTM! Great job!