Release locks when closing draft PRs

[andrewring]

If plan is run manually in a draft PR, the PR may hold locks. If the draft PR is then closed, without first marking it Ready For Review, the locks are left in place. To resolve this, we can process closing draft PRs in the same way as non-draft PRs.

Also collapses draft event parsing test into normal event parsing. Previous test did not actually test different event types.

[codecov]

Codecov Report

Merging #1038 into master will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1038      +/-   ##
==========================================
+ Coverage   71.96%   71.98%   +0.01%     
==========================================
  Files          65       65              
  Lines        5429     5432       +3     
==========================================
+ Hits         3907     3910       +3     
  Misses       1215     1215              
  Partials      307      307              

Impacted Files	Coverage Δ
server/events/event_parser.go	86.19% <100.00%> (+0.09%)	⬆️

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[lkysow]

Thanks!