feat(healthz-server): add option to customize port

[EshaanAgg]

What type of PR is this?
Adds option to customize the port for the healthz server, while maintaining the default one to be 8081.

What this PR does / why we need it:
The same port for the health server causes port conflicts in parallel test runs.

Which issue(s) this PR fixes:
Fixes #5149

Release Notes: Yes

new features: |
    Added support to configure the Healthz Probe server port in FileProvider API & KubernetesProvider API.

[EshaanAgg]

Hi @shawnh2! Can you please run the workflows for this PR and review it whenever possible? Thanks.

[EshaanAgg]

Hi! Is there something required from my end for the review of this PR?

[shawnh2]

Minor comments, code overall LGTM

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 66.87%. Comparing base (48459d4) to head (b7b67f5).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5151      +/-   ##
==========================================
+ Coverage   66.85%   66.87%   +0.01%     
==========================================
  Files         210      210              
  Lines       32998    33003       +5     
==========================================
+ Hits        22061    22070       +9     
+ Misses       9595     9593       -2     
+ Partials     1342     1340       -2     

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[EshaanAgg]

@shawnh2 The build seems to have failed due to a network error while installing the dependencies for the build action and not due to any code changes. Can you please re-run that workflow?

[shawnh2]

LGTM thanks

[zirain]

what about kubernetes provider?

[shawnh2]

what about kubernetes provider?

discussed in #5151 (comment), leave it until we have any user requests

[zirain]

then we need to highlight in api.