add warning log when task_key>100 (#42813)

related to #41816

Adds a warning log to indicate failure if length of task_key>100.

airflow/providers/databricks/operators/databricks.py

@@ -1045,7 +1045,15 @@ def _get_hook(self, caller: str) -> DatabricksHook:
 
     def _get_databricks_task_id(self, task_id: str) -> str:
         """Get the databricks task ID using dag_id and task_id. Removes illegal characters."""
-        return f"{self.dag_id}__{task_id.replace('.', '__')}"
+        task_id = f"{self.dag_id}__{task_id.replace('.', '__')}"
+        if len(task_id) > 100:
+            self.log.warning(
+                "The generated task_key '%s' exceeds 100 characters and will be truncated by the Databricks API. "
+                "This will cause failure when trying to monitor the task. task_key is generated by ",
+                "concatenating dag_id and task_id.",
+                task_id,
+            )
+        return task_id
 
     @property
     def _databricks_workflow_task_group(self) -> DatabricksWorkflowTaskGroup | None: