Deprecate legacy policy approval status in API

What does this MR do and why?

We deprecated legacy names for approval status of license policy (blacklisted, approved) but they are still used in our API queries and responses. We need to fix it.

Issue to remove those statuses completely and change this status in the response: #345839 (closed)

Screenshots or screen recordings

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How to set up and validate locally

Run

curl --data "name=MIT&approval_status=denied" --header "PRIVATE-TOKEN: <your_access_token>" "{GDK:port}/api/v4/projects/1/managed_licenses"

It should create a new entry in SoftwareLicensePolicy and this policy should be denied.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #335707 (closed)