fix: gRPC Monitor call does not emit applied_settings response

[cmaglie]

Please check if the PR fulfills these requirements

See how to contribute

• The PR has no duplicates (please search among the Pull Requests
  before creating one)
• The PR follows
  our contributing guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• UPGRADING.md has been updated with a migration guide (for breaking changes)
• configuration.schema.json updated if new parameters are added.

What kind of change does this PR introduce?

Fixes the problem described in detail in #2965

What is the current behavior?

The gRPC Monitor call does not emit applied_settings response

What is the new behavior?

The gRPC Monitor call does emit applied_settings response, both after opening the port, and after applying changes.

Does this PR introduce a breaking change, and is titled accordingly?

No

Other information

Fix #2965

[codecov]

Codecov Report

❌ Patch coverage is 77.27273% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 69.48%. Comparing base (dd407d4) to head (73c3b5f).
⚠️ Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
commands/service_monitor.go	77.27%	1 Missing and 4 partials ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3191   +/-   ##
=======================================
  Coverage   69.48%   69.48%           
=======================================
  Files         252      252           
  Lines       19557    19585   +28     
=======================================
+ Hits        13589    13609   +20     
- Misses       4710     4713    +3     
- Partials     1258     1263    +5     

Flag	Coverage Δ
unit	69.48% <77.27%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

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