fix: safer error message in alerts (#27019)

(cherry picked from commit 686ce33ea5)

superset/commands/report/alert.py

@@ -150,7 +150,7 @@ class AlertCommand(BaseCommand):
                 rendered_sql, ALERT_SQL_LIMIT
             )
 
-            _, username = get_executor(
+            executor, username = get_executor(  # pylint: disable=unused-variable
                 executor_types=app.config["ALERT_REPORTS_EXECUTE_AS"],
                 model=self._report_schedule,
             )
@@ -169,7 +169,12 @@ class AlertCommand(BaseCommand):
             logger.warning("A timeout occurred while executing the alert query: %s", ex)
             raise AlertQueryTimeout() from ex
         except Exception as ex:
-            raise AlertQueryError(message=str(ex)) from ex
+            logger.exception("An error occurred when running alert query")
+            # The exception message here can reveal to much information to malicious
+            # users, so we raise a generic message.
+            raise AlertQueryError(
+                message=_("An error occurred when running alert query")
+            ) from ex
 
     def validate(self) -> None:
         """