Do not filter annotation motivations by default

[marlo-longley]

This is a proposal to address #4209, based on the discussion in the 11/20/2025 Mirador community call. During that call I understood that we wanted to stop filtering annotation motivations by default. This PR achieves that while leaving open the option of filtering by motivation if desired.

This is a potentially a breaking change in the case of a blank filteredMotivations array in settings. Before this PR, no annotations would be rendered in that case. But in the case that you've added values to this array, the behavior will remain the same. Given that the default setting previously included values, I don't think many people would be operating with an empty array in the wild.

There is probably a lot of history behind this filter, but my knowledge is recent. Open to other proposals.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.1%. Comparing base (25c0b0e) to head (473c722).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #4218     +/-   ##
=======================================
+ Coverage   95.1%   95.1%   +0.1%     
=======================================
  Files        326     326             
  Lines      16193   16196      +3     
  Branches    2546    2548      +2     
=======================================
+ Hits       15392   15395      +3     
  Misses       796     796             
  Partials       5       5             

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