[refactor] Remove unnecessary implements for InternalPriorityQueue (#26315)

Author: beliefer

flink-runtime/src/main/java/org/apache/flink/runtime/state/heap/KeyGroupPartitionedPriorityQueue.java

@@ -48,7 +48,7 @@
  */
 public class KeyGroupPartitionedPriorityQueue<
                 T, PQ extends InternalPriorityQueue<T> & HeapPriorityQueueElement>
-        implements InternalPriorityQueue<T>, KeyGroupedInternalPriorityQueue<T> {
+        implements KeyGroupedInternalPriorityQueue<T> {
 
     /** A heap of heap sets. Each sub-heap represents the partition for a key-group. */
     @Nonnull private final HeapPriorityQueue<PQ> heapOfKeyGroupedHeaps;