IAM: Add the implementation of the Update User API (#112054)

* wip

* Add validate, wire mutate, add tests

* Address copilot's feedback

* Address feedback

pkg/registry/apis/iam/legacy/update_user.sql

@@ -0,0 +1,11 @@
+-- name: update_user
+UPDATE {{ .Ident .UserTable }}
+SET
+	login = {{ .Arg .Command.Login }},
+	email = {{ .Arg .Command.Email }},
+	name = {{ .Arg .Command.Name }},
+	is_admin = {{ .Arg .Command.IsAdmin }},
+	is_disabled = {{ .Arg .Command.IsDisabled }},
+	email_verified = {{ .Arg .Command.EmailVerified }},
+	updated = {{ .Arg .Command.Updated }}
+WHERE uid = {{ .Arg .Command.UID }}