events/loop: drain queue on close

[JoshVanL]

Update looper to drain the Enqueue loop in the event that an error has occurred when Enqueuing. Handle an error'd Run on Close by respecting the closedCh channel.

Fixes a deadlock which can occur in the event a Handle func returns an error, then trying to Close.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.

Project coverage is 73.61%. Comparing base (26b564d) to head (3374dea).
Report is 20 commits behind head on main.

Files with missing lines	Patch %	Lines
events/loop/loop.go	0.00%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #124      +/-   ##
==========================================
- Coverage   79.73%   73.61%   -6.13%     
==========================================
  Files          62       82      +20     
  Lines        4768     5852    +1084     
==========================================
+ Hits         3802     4308     +506     
- Misses        811     1365     +554     
- Partials      155      179      +24     

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