Use thin/passthrough hook instead of one-liner hook method (#29252)

Use the hook to get a boto connection and make the api call from
operator method. Defining one-liner hook methods that are just calling
boto are not ideal.

airflow/providers/amazon/aws/hooks/emr.py

@@ -179,15 +179,6 @@ def add_job_flow_steps(
                 )
         return response["StepIds"]
 
-    def terminate_job_flow(self, job_flow_id: str) -> None:
-        """
-        Terminate a given EMR cluster (job flow) by id. If TerminationProtected=True on the cluster,
-        termination will be unsuccessful.
-
-        :param job_flow_id: id of the job flow to terminate
-        """
-        self.get_conn().terminate_job_flows(JobFlowIds=[job_flow_id])
-
     def test_connection(self):
         """
         Return failed state for test Amazon Elastic MapReduce Connection (untestable).

airflow/providers/amazon/aws/operators/emr.py

@@ -611,10 +611,13 @@ def execute(self, context: Context) -> str | None:
             return self._job_flow_id
 
     def on_kill(self) -> None:
-        """Terminate job flow."""
+        """
+        Terminate the EMR cluster (job flow). If TerminationProtected=True on the cluster,
+        termination will be unsuccessful.
+        """
         if self._job_flow_id:
             self.log.info("Terminating job flow %s", self._job_flow_id)
-            self._emr_hook.terminate_job_flow(self._job_flow_id)
+            self._emr_hook.conn.terminate_job_flows(JobFlowIds=[self._job_flow_id])
 
 
 class EmrModifyClusterOperator(BaseOperator):