chore: adding common function for error reporting for constraint

[JaydipGabani]

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, using fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when the PR gets merged):
Fixes #3484

Special notes for your reviewer:
Here is how the constraint status looks after this change -

status:
    byPod:
    - constraintUID: d50a2340-d4de-4bfd-8cb7-5ecbd645e9b1
      enforced: true
      errors:
      - code: ""
        message: 'cannot generate ValidatingAdmissionPolicyBinding: ValidatingAdmissionPolicy
          API is not enabled'
      id: gatekeeper-audit-78dd48444d-9k6h7
      observedGeneration: 1
      operations:
      - audit
      - mutation-status
      - status
    - constraintUID: d50a2340-d4de-4bfd-8cb7-5ecbd645e9b1
      enforced: true
      errors:
      - code: ""
        message: 'cannot generate ValidatingAdmissionPolicyBinding: ValidatingAdmissionPolicy
          API is not enabled'
      id: gatekeeper-controller-manager-c86c8b5-2g7pn
      observedGeneration: 1
      operations:
      - mutation-webhook
      - webhook
    - constraintUID: d50a2340-d4de-4bfd-8cb7-5ecbd645e9b1
      enforced: true
      errors:
      - code: ""
        message: 'cannot generate ValidatingAdmissionPolicyBinding: ValidatingAdmissionPolicy
          API is not enabled'
      id: gatekeeper-controller-manager-c86c8b5-k9sxf
      observedGeneration: 1
      operations:
      - mutation-webhook
      - webhook
    - constraintUID: d50a2340-d4de-4bfd-8cb7-5ecbd645e9b1
      enforced: true
      errors:
      - code: ""
        message: 'cannot generate ValidatingAdmissionPolicyBinding: ValidatingAdmissionPolicy
          API is not enabled'
      id: gatekeeper-controller-manager-c86c8b5-zx89k
      observedGeneration: 1
      operations:
      - mutation-webhook
      - webhook

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 28.57143% with 15 lines in your changes missing coverage. Please review.

Project coverage is 48.16%. Comparing base (3350319) to head (f751249).
Report is 148 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/controller/constraint/constraint_controller.go	28.57%	15 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (3350319) and HEAD (f751249). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (3350319)	HEAD (f751249)
unittests	2	1

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3486      +/-   ##
==========================================
- Coverage   54.49%   48.16%   -6.33%     
==========================================
  Files         134      218      +84     
  Lines       12329    15134    +2805     
==========================================
+ Hits         6719     7290     +571     
- Misses       5116     7029    +1913     
- Partials      494      815     +321     

Flag	Coverage Δ
unittests	48.16% <28.57%> (-6.33%)	⬇️

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[maxsmythe]

What happens to the reportMetrics flag?

[JaydipGabani]

Added the flag back. This was not supposed to be removed. Good catch!

[maxsmythe]

LGTM

[ritazh]

LGTM