API: Add updatedAt to api/users/:id (#19004)

* API: Add `updatedAt` to api/users/:id

This adds the timestamp of when a particular user was last updated to
the `api/users/:id` endpoint.

This helps our administrators understand when was the user information last
updated. Particularly when it comes from external systems e.g. LDAP

pkg/services/sqlstore/user.go

@@ -331,6 +331,7 @@ func GetUserProfile(query *models.GetUserProfileQuery) error {
 		IsGrafanaAdmin: user.IsAdmin,
 		IsDisabled:     user.IsDisabled,
 		OrgId:          user.OrgId,
+		UpdatedAt:      user.Updated,
 	}
 
 	return err