refactor(sysadvisor): add idle status for region

[cheney-lin]

What type of PR is this?

Enhancements

What this PR does / why we need it:

Which issue(s) this PR fixes:

Special notes for your reviewer:

[codecov]

Codecov Report

Attention: 13 lines in your changes are missing coverage. Please review.

Comparison is base (5e7887c) 54.91% compared to head (5fe1fe3) 54.86%.

Files	Patch %	Lines
...urce/cpu/region/region_dedicated_numa_exclusive.go	58.33%	10 Missing ⚠️
...plugin/qosaware/resource/cpu/region/region_base.go	25.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #468      +/-   ##
==========================================
- Coverage   54.91%   54.86%   -0.06%     
==========================================
  Files         503      503              
  Lines       54789    54816      +27     
==========================================
- Hits        30088    30074      -14     
- Misses      21455    21502      +47     
+ Partials     3246     3240       -6     

Flag	Coverage Δ
unittest	54.86% <55.17%> (-0.06%)	⬇️

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