refactor: use Angular property binding for SVG fill attribute.

[Jasonlee6789]

This PR replaces attr.fill="{{ fillRef }}" with [attr.fill]="fillRef" in SVG polygon bindings for improved Angular consistency and maintainability. The property binding syntax [attr.fill] is the standard Angular approach for dynamic attribute values, ensuring type safety, better template parsing, and alignment with the rest of the codebase.

[codecov[bot]]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests.

Additional details and impacted files

@@              Coverage Diff              @@
##             develop    #3377      +/-   ##
=============================================
+ Coverage      59.78%   59.86%   +0.08%     
  Complexity       112      112              
=============================================
  Files           2785     2787       +2     
  Lines         120785   121037     +252     
  Branches        9015     9061      +46     
=============================================
+ Hits           72205    72452     +247     
+ Misses         45901    45869      -32     
- Partials        2679     2716      +37     

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[da-Kai]

@Jasonlee6789 thanks. Looks good to me 👍