Fix test goroutine leaks in ./cmd/collector/app/

[WillSewell]

Which problem is this PR solving?

Solves part of #5006.

Description of the changes

I introduced testutils.VerifyGoLeaks(m) and then ensured all leaked goroutines were stopped.

How was this change tested?

make lint and make test

Checklist

• I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• I have signed all commits
• I have added unit tests for the new functionality
• I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: yarn lint and yarn test

[yurishkuro]

Please make sure all commits are signed. See CONTRIBUTING.md

[WillSewell]

Sorry, just force-pushed a signed commit.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.08%. Comparing base (db8c04c) to head (2b0c4dd).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5292      +/-   ##
==========================================
+ Coverage   95.06%   95.08%   +0.01%     
==========================================
  Files         340      340              
  Lines       16610    16615       +5     
==========================================
+ Hits        15791    15798       +7     
+ Misses        630      629       -1     
+ Partials      189      188       -1     

Flag	Coverage Δ
badger	13.26% <ø> (ø)
cassandra-3.x	26.44% <ø> (ø)
cassandra-4.x	26.44% <ø> (ø)
elasticsearch-5.x	21.70% <ø> (ø)
elasticsearch-6.x	21.70% <ø> (+0.01%)	⬆️
elasticsearch-7.x	21.77% <ø> (ø)
elasticsearch-8.x	21.87% <ø> (ø)
grpc	10.89% <ø> (-0.02%)	⬇️
kafka	14.73% <ø> (ø)
opensearch-1.x	21.77% <ø> (-0.02%)	⬇️
opensearch-2.x	21.78% <ø> (+0.01%)	⬆️
unittests	92.31% <100.00%> (+0.01%)	⬆️

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[WillSewell]

Thanks for the approval @pavolloffay (also thanks for hosting the kubecon contribfest - I was there!)

Could you add the label that is causing CI to fail please? I don't think I have permission.

[yurishkuro]

Thanks!