Add ReactionController to disable button during submits

[pixeldesu]

Fixes #1517 (actually, other changes beforehand fixed it already, but this one might as well close it)

Testing:

• Make your internet slow, reload the page and try submitting the button multiple times. It should get disabled until the smile went through.

Note: Don't forget to rebuild JS.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (855d0fa) 95.71% compared to head (96aeb16) 95.71%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1533   +/-   ##
=======================================
  Coverage   95.71%   95.71%           
=======================================
  Files         174      174           
  Lines        2704     2704           
=======================================
  Hits         2588     2588           
  Misses        116      116           

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