Update deprecation notices for runner API endpoints

What does this MR do?

Updates deprecation notices for the Runner API endpoints, as the decision to remove the endpoints by a certain milestone was changed. Endpoints can only be removed with a new REST API version, not at a particular milestone.

In GitLab 17.0, registration tokens will be removed and as a result the following endpoints will no longer work:

• Reset instance’s runner registration token
• Reset project’s runner registration token
• Reset group’s runner registration token

Related issues

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