[8.8] Security tech debt cleanup (#157990) (#158234)

# Backport

This will backport the following commits from `main` to `8.8`:
- [Security tech debt cleanup
(#157990)](#157990)

<!--- Backport version: 8.9.7 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Thom
Heymann","email":"190132+thomheymann@users.noreply.github.com"},"sourceCommit":{"committedDate":"2023-05-23T08:30:48Z","message":"Security
tech debt cleanup (#157990)\n\n## Summary\r\n\r\nThis PR cleans up some
outstanding tech debt.\r\n\r\n### 1. Remove deprecation warning for
`disabled` prop\r\n\r\nThis property was marked as deprecated the moment
it was introduced
(See\r\nhttps://github.com//pull/118001/files#r753124740).
However\r\nit has been adopted by Fleet and Guided Onboarding plugins so
I don't\r\nthink there's value in keeping this deprecation warning in
place.\r\n\r\nAs an alternative we could also bump the `@removeBy`
version if people\r\nthink we should still remove this
property.\r\n\r\n\r\n### ~~2. Remove deprecated property
`requiredRoles`~~\r\n\r\n~~This property has been deprecated and marked
for removal for 8.8. The\r\nproperty isn't being used anywhere in our
codebase and we have reached\r\nfeature freeze for 8.8 so looks safe to
be removed now.~~\r\n\r\nTurns out this property is still used and can't
be removed without\r\nbreaking existing functionality so reverting that
commit.","sha":"3800ce4c9cbbceaa861b62de2fd217f0c1961b98","branchLabelMapping":{"^v8.9.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["Team:Security","release_note:skip","v8.9.0","v8.8.1"],"number":157990,"url":"#157990
tech debt cleanup (#157990)\n\n## Summary\r\n\r\nThis PR cleans up some
outstanding tech debt.\r\n\r\n### 1. Remove deprecation warning for
`disabled` prop\r\n\r\nThis property was marked as deprecated the moment
it was introduced
(See\r\nhttps://github.com//pull/118001/files#r753124740).
However\r\nit has been adopted by Fleet and Guided Onboarding plugins so
I don't\r\nthink there's value in keeping this deprecation warning in
place.\r\n\r\nAs an alternative we could also bump the `@removeBy`
version if people\r\nthink we should still remove this
property.\r\n\r\n\r\n### ~~2. Remove deprecated property
`requiredRoles`~~\r\n\r\n~~This property has been deprecated and marked
for removal for 8.8. The\r\nproperty isn't being used anywhere in our
codebase and we have reached\r\nfeature freeze for 8.8 so looks safe to
be removed now.~~\r\n\r\nTurns out this property is still used and can't
be removed without\r\nbreaking existing functionality so reverting that
commit.","sha":"3800ce4c9cbbceaa861b62de2fd217f0c1961b98"}},"sourceBranch":"main","suggestedTargetBranches":["8.8"],"targetPullRequestStates":[{"branch":"main","label":"v8.9.0","labelRegex":"^v8.9.0$","isSourceBranch":true,"state":"MERGED","url":"#157990
tech debt cleanup (#157990)\n\n## Summary\r\n\r\nThis PR cleans up some
outstanding tech debt.\r\n\r\n### 1. Remove deprecation warning for
`disabled` prop\r\n\r\nThis property was marked as deprecated the moment
it was introduced
(See\r\nhttps://github.com//pull/118001/files#r753124740).
However\r\nit has been adopted by Fleet and Guided Onboarding plugins so
I don't\r\nthink there's value in keeping this deprecation warning in
place.\r\n\r\nAs an alternative we could also bump the `@removeBy`
version if people\r\nthink we should still remove this
property.\r\n\r\n\r\n### ~~2. Remove deprecated property
`requiredRoles`~~\r\n\r\n~~This property has been deprecated and marked
for removal for 8.8. The\r\nproperty isn't being used anywhere in our
codebase and we have reached\r\nfeature freeze for 8.8 so looks safe to
be removed now.~~\r\n\r\nTurns out this property is still used and can't
be removed without\r\nbreaking existing functionality so reverting that
commit.","sha":"3800ce4c9cbbceaa861b62de2fd217f0c1961b98"}},{"branch":"8.8","label":"v8.8.1","labelRegex":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Thom Heymann <190132+thomheymann@users.noreply.github.com>

x-pack/plugins/features/common/feature_kibana_privileges.ts

@@ -22,8 +22,6 @@ export interface FeatureKibanaPrivileges {
 
   /**
    * Whether or not this privilege should be hidden in the roles UI and disallowed on the API. Defaults to `false`.
-   * @deprecated
-   * @removeBy 8.8.0
    */
   disabled?: boolean;