fix: only allow execution_time passed by keyword

Author: makaroni4

sqlmesh/core/context.py

@@ -2247,8 +2247,8 @@ def audit(
         self,
         start: TimeLike,
         end: TimeLike,
-        execution_time: t.Optional[TimeLike] = None,
         *,
+        execution_time: t.Optional[TimeLike] = None,
         models: t.Optional[t.Iterator[str]] = None,
     ) -> bool:
         """Audit models.