Api service account user creation self managed

What does this MR do and why?

For #406782 (closed)

Screenshots or screen recordings

Please find below the output for curl request -

curl --location --request POST 'https://gdk.test:3443/api/v4/service_accounts' --header 'PRIVATE-TOKEN:' --header 'Content-Type: application/json'

curl --location --request POST 'https://gdk.test:3443/api/v4/users' --data '{"name":"smriti","email":"sgarg7@gitlab.com","password":"1234%^&*","service_account":"false","username":"sgarg7"}' --header 'PRIVATE-TOKEN: <test_token>' --header 'Content-Type: application/json'

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

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