Add max three app name status for agent control health check

[umaannamalai]

This PR adds a new status code to the agent that sets health check reporting to unhealthy when a user has configured more than 3 app names.

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ PYTHON	bandit	2		0	6.62s
✅ PYTHON	black	3	1	0	4.84s
✅ PYTHON	flake8	3		0	1.09s
✅ PYTHON	isort	3	3	0	0.27s
✅ PYTHON	pylint	3		0	7.01s

See detailed report in MegaLinter reports
Set VALIDATE_ALL_CODEBASE: true in mega-linter.yml to validate all sources, not only the diff

MegaLinter is graciously provided by

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.

Project coverage is 79.72%. Comparing base (3af452b) to head (034b6e7).
Report is 61 commits behind head on super-agent.

Files with missing lines	Patch %	Lines
newrelic/core/agent_control_health.py	50.00%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           super-agent    #1291      +/-   ##
===============================================
- Coverage        79.74%   79.72%   -0.02%     
===============================================
  Files              202      202              
  Lines            22352    22360       +8     
  Branches          3545     3546       +1     
===============================================
+ Hits             17825    17827       +2     
- Misses            3370     3372       +2     
- Partials          1157     1161       +4     

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

[hmstepanek]

There's one linter issue but otherwise looks good to me:

newrelic/core/agent_control_health.py:68:1: E302 expected 2 blank lines, found 1