Fix comment HTTP updates canceled via race condition (fixes #2603)

[benvinegar]

Fixed by moving the deletion logic higher to a higher-level container component (the component that does the actual DOM removal when the GroupStore changes).

[benvinegar]

cc @mattrobenolt

[codecov-io]

Current coverage is 83.22%

Merging #2636 into master will not affect coverage as of d71887c

@@            master   #2636   diff @@
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  Files          864     864       
  Stmts        32664   32664       
  Branches         0       0       
  Methods          0       0       
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- Hit          27186   27183     -3
  Partial          0       0       
- Missed        5478    5481     +3

Review entire Coverage Diff as of d71887c

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Uncovered Suggestions

1. +0.07% via ...try/utils/apidocs.py#414...436
2. +0.07% via ...try/utils/apidocs.py#117...139
3. +0.06% via ...gs/sentry_helpers.py#191...211
4. See 7 more...

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