Allow custom subject lines for password request

Summary The requestPasswordReset function in the users service accepts subject as an optional field, only this parameter is not passed in the /auth/password/request API route parameters. I have no idea why, but I'd like to propose a pull request to implement this oversight. Basic Example The basic API call is as follows: The new one would be : Motivation I need to be able to customize the title of the email that's sent out regarding the password reset request for non-English-speaking users in particular. Detailed Design The implementation has already been done on Directus, and only the function calling the service has been modified. Requirements List Must Have: • Custom emails subjects for request password Drawbacks Subject can be treated as an optional field, allowing for backwards compatibility. The existing implementation of the request password feature can remain unchanged. Alternatives N/A Adoption Strateg…