API: Add createdAt field to /api/users/:id (#19475)

It would help for auditing purposes to have the user's created date exposed via the API along with the other fields already exposed via the API.

pkg/services/sqlstore/user.go

@@ -332,6 +332,7 @@ func GetUserProfile(query *models.GetUserProfileQuery) error {
 		IsDisabled:     user.IsDisabled,
 		OrgId:          user.OrgId,
 		UpdatedAt:      user.Updated,
+		CreatedAt:      user.Created,
 	}
 
 	return err