Add missing kind constants for API

[willie-yao]

What type of PR is this?
/kind cleanup

What this PR does / why we need it:
This PR is a follow up to #4155 that adds constants for kinds. Comment here: #4155 (review)

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

Special notes for your reviewer:

• cherry-pick candidate

TODOs:

• squashed commits
• includes documentation
• adds unit tests

Release note:

NONE

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (224b7dc) 59.73% compared to head (a31848b) 59.73%.
Report is 3 commits behind head on main.

❗ Current head a31848b differs from pull request most recent head 337ce25. Consider uploading reports for the commit 337ce25 to get more accurate results

Files	Patch %	Lines
azure/scope/managedcontrolplane.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4287   +/-   ##
=======================================
  Coverage   59.73%   59.73%           
=======================================
  Files         192      192           
  Lines       19303    19303           
=======================================
  Hits        11531    11531           
  Misses       7142     7142           
  Partials      630      630           

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[CecileRobertMichon]

Thank you!

/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: bd455793db6c748d30bd11ea902e2dec9f7cac1a

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CecileRobertMichon

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