[frontend] Add support for dynamic configurable required fields to Events

[VerboseCat]

Proposed changes

This PR builds upon the capabilities from #6972. This PR will add all capabilities from the previous PR to the 'Events' section of the platform, to include creating and editing the following entity types:

• Incidents
• Observed Data
• Sightings

Related issues

• As stated in Initial Changes to support dynamic configurable required fields via settings --> customization #6972, the External-Reference field is not directly supported for this required fields change. Based on communication with the Filigran team - this field will require many complex relationships between mandatory attributes to fully implement.

Checklist

• I consider the submitted work as finished
• I tested the code for its functionality
• (N/A - Existing test cases should work properly) I wrote test cases for the relevant uses case (coverage and e2e)
• I added/update the relevant documentation (either on github or on notion)
• Where necessary I refactored code to improve the overall quality

Further comments

• The customization menu for 'Observed Data' includes a 'Content' field, but there is no 'Content' field in either the create or edit form, so requiring this field makes it impossible to submit the form.

• Incident and Observed Data creation forms include the field objectLabel but the edit forms do not. This field is not in the 'Customization' menu. Adding it would break the edit forms.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 64.60%. Comparing base (2c1be7f) to head (fe159a9).

Additional details and impacted files

@@                Coverage Diff                @@
##           release/6.4.0    #8960      +/-   ##
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+ Coverage          64.59%   64.60%   +0.01%     
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  Files                614      614              
  Lines              58902    58902              
  Branches            6476     6477       +1     
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+ Hits               38046    38053       +7     
+ Misses             20856    20849       -7     

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