Login as arbitrary user when acting as admin

Summary We would like a mechanism for logging in an arbitrary user using an admin's access_token (without knowing the users password). This would enable us to custom-build "magic link" login user-flows. Currently, it's only possible to programmatically login a user with the /auth/login endpoint, but the user's password is a required field, so it must be known. Eg. We would like to be able to circumvent the password field by passing an Admin API token (using the typical authentication strategy: passing an access_token in the query-string, or by passing an Authorization header). Eg. Alternatively, this could be a new endpoint altogether, so that the signature of the existing /auth/login endpoint would remain the same (password as a "required" field). Basic Example Given above. _No response_ Motivation This has at least two utilities, which would be of value to us. 1. Custom Authentication Mechanisms We could imp…