Fix connection reset logic to ensure the old subscribe goroutine is cancelled before a new connection is made

[dhurley]

Proposed changes

• A gRPC server that is tracking connections could remove a connection when the Subscribe stream is closed by the client and then track a connection again if it receives a CreateConnection RPC call. So we need to ensure that the old subscribe goroutine is cancelled before a new connection is made when a connection reset happens to ensure that the server is able to track connections.
• Also I spotted a potential race condition in file service operator so I provided a fix for that as well.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• I have run make install-tools and have attached any dependency changes to this pull request
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• If applicable, I have updated any relevant documentation (README.md)
• If applicable, I have tested my cross-platform changes on Ubuntu 22, Redhat 8, SUSE 15 and FreeBSD 13

[codecov]

Codecov Report

❌ Patch coverage is 70.58824% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.01%. Comparing base (8dd9122) to head (4299490).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/file/file_service_operator.go	64.70%	2 Missing and 4 partials ⚠️
internal/command/command_plugin.go	76.47%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1700   +/-   ##
=======================================
  Coverage   85.00%   85.01%           
=======================================
  Files         104      104           
  Lines       13579    13596   +17     
=======================================
+ Hits        11543    11558   +15     
- Misses       1522     1524    +2     
  Partials      514      514           

Files with missing lines	Coverage Δ
internal/command/command_plugin.go	71.60% <76.47%> (+0.79%)	⬆️
internal/file/file_service_operator.go	77.47% <64.70%> (-0.07%)	⬇️

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 8dd9122...4299490. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[karensantana]

question: Are we missing a cp.subscribeWg.Wait() statement?

[karensantana]

nitpick: Trailing dot.