MINOR: Remove tag from metric to measure process-rate on source nodes (#8175)

Reviewers: Guozhang Wang <wangguoz@gmail.com>

streams/src/main/java/org/apache/kafka/streams/processor/internals/metrics/ProcessorNodeMetrics.java

@@ -137,7 +137,7 @@ public class ProcessorNodeMetrics {
         addInvocationRateAndCountToSensor(
             parentSensor,
             TASK_LEVEL_GROUP,
-            streamsMetrics.nodeLevelTagMap(threadId, taskId, ROLLUP_VALUE),
+            streamsMetrics.taskLevelTagMap(threadId, taskId),
             PROCESS,
             PROCESS_RATE_DESCRIPTION,
             PROCESS_TOTAL_DESCRIPTION

streams/src/test/java/org/apache/kafka/streams/processor/internals/SourceNodeTest.java

@@ -112,8 +112,8 @@ public class SourceNodeTest {
             assertTrue(StreamsTestUtils.containsMetric(metrics, "process-total", groupName, metricTags));
 
             // test parent sensors
-            metricTags.put("processor-node-id", StreamsMetricsImpl.ROLLUP_VALUE);
             final String parentGroupName = "stream-task-metrics";
+            metricTags.remove("processor-node-id");
             assertTrue(StreamsTestUtils.containsMetric(metrics, "process-rate", parentGroupName, metricTags));
             assertTrue(StreamsTestUtils.containsMetric(metrics, "process-total", parentGroupName, metricTags));
 

streams/src/test/java/org/apache/kafka/streams/processor/internals/metrics/ProcessorNodeMetricsTest.java

@@ -121,7 +121,7 @@ public class ProcessorNodeMetricsTest {
         final String descriptionOfRate = "The average number of calls to process per second";
         expect(streamsMetrics.taskLevelSensor(THREAD_ID, TASK_ID, metricNamePrefix, RecordingLevel.DEBUG))
             .andReturn(expectedParentSensor);
-        expect(streamsMetrics.nodeLevelTagMap(THREAD_ID, TASK_ID, StreamsMetricsImpl.ROLLUP_VALUE))
+        expect(streamsMetrics.taskLevelTagMap(THREAD_ID, TASK_ID))
             .andReturn(parentTagMap);
         StreamsMetricsImpl.addInvocationRateAndCountToSensor(
             expectedParentSensor,