[Media ML] Sync with original implementation

Originally, a volume key long press listener would have been called
for the first ACTION_DOWN KeyEvent with repeat count equal to 0, but
the new implementation does not call it.
This CL fixes the current implementation to match the original
implementation.

Bug: 157988289
Test: manually
Change-Id: I563215fc522e952412ebbae1ddaa1a6b1b646c53

services/core/java/com/android/server/media/MediaSessionService.java

@@ -2572,6 +2572,9 @@ public class MediaSessionService extends SystemService implements Monitor {
                     }
                 } else {
                     if (mKeyType == KEY_TYPE_VOLUME) {
+                        if (isFirstLongPressKeyEvent(keyEvent)) {
+                            dispatchVolumeKeyLongPressLocked(mTrackingFirstDownKeyEvent);
+                        }
                         dispatchVolumeKeyLongPressLocked(keyEvent);
                     } else if (isFirstLongPressKeyEvent(keyEvent)
                             && isVoiceKey(keyEvent.getKeyCode())) {