fix: properly return error on invalid CQL2 filters

Author: alukach

src/stac_auth_proxy/middleware/Cql2BuildFilterMiddleware.py

@@ -93,7 +93,7 @@ async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
             cql2_filter.validate()
         except ValidationError:
             logger.error("Invalid CQL2 filter: %s", filter_expr)
-            return await Response(status_code=502, content="Invalid CQL2 filter")
+            return Response(status_code=502, content="Invalid CQL2 filter")
         setattr(request.state, self.state_key, cql2_filter)
 
         return await self.app(scope, receive, send)