Fix bug in setting the correct collector state after a config change event.

[kovrus]

Description:
After configuration is updated the collector state will be stuck at Starting even tho the collector has started completely.

Link to tracking Issue:
Fixes #5830.

Testing:
Unit tests.

[codecov]

Codecov Report

Merging #5896 (1eb9dd8) into main (e89786d) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #5896      +/-   ##
==========================================
+ Coverage   91.44%   91.47%   +0.03%     
==========================================
  Files         195      195              
  Lines       11933    11933              
==========================================
+ Hits        10912    10916       +4     
+ Misses        811      804       -7     
- Partials      210      213       +3     

Impacted Files	Coverage Δ
service/collector.go	78.87% <100.00%> (+2.81%)	⬆️

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[bogdandrutu]

Looks like tests are not passing https://github.com/open-telemetry/opentelemetry-collector/runs/7811347371?check_suite_focus=true#step:6:3292

[kovrus]

Looks like tests are not passing https://github.com/open-telemetry/opentelemetry-collector/runs/7811347371?check_suite_focus=true#step:6:3292

Closing collector properly in tests via collector api, seems to fix the race condition. (at least, I couldn't reproduce it locally any longer)