fix: Add custom attribute for OptionValue and OptionLabel and allow empty string

[standeren]

Description

Add new custom [NotNullable] attribute for Value and Label fields in Option class in order to avoid [Required] attribute that denies empty strings including null. According to the json schemas from Apps that defines Options, empty strings are allowed, so our backend should also allow this.

Additional improvements:

• Add OptionsFormatExceptionsFilter in order to be able to pass informative exceptions when value is assigned an invalid type
• Adapt Value and Label fields in Option class to use required property that is evaluated during deserialization, which allowed us to remove some custom null-validation code
• Add tests for upload options endpoint
• Add validation when fetching options from repo
• Add test checking for 400 when fetching invalid options

Related Issue(s)

• #{issue number}

Verification

• Your code builds clean without any errors or warnings
• Manual testing done (required)
• Relevant automated test added (if you find this hard, leave it and we'll help out)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.32%. Comparing base (7840b40) to head (907f422).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #14035   +/-   ##
=======================================
  Coverage   95.32%   95.32%           
=======================================
  Files        1775     1775           
  Lines       23128    23128           
  Branches     2685     2685           
=======================================
  Hits        22047    22047           
  Misses        833      833           
  Partials      248      248           

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[ErlingHauan]

Nice work! Great that you also spotted the missing tests and took action. It's a reminder for me to get familiar with code coverage in my editor. But it would be nice if we had code coverage in the pipeline for backend as well 😬

[Konrad-Simso]

Nice work 🚀