Allow dispatcher to be idle after metrics push

Earlier, the dispatcher was not being allowed to enter idle state
since processLatencyStatisticsLocked() would always wake it up in 6 hours,
causing many of the dispatcher tests to fail.
Now, the dispatcher will be idle after the latency statistics are
pushed. After the statistics push is complete, the next push will occur
after 6 hours upon the next input event being received by the
dispatcher.

Bug: 270049345
Test: atest inputflinger_tests
Flag: com.android.input.flags.enable_per_device_input_latency_metrics
Change-Id: I1cdb6df6110bff9e4fcb6cbfdc91c16c8e386f0b
diff --git a/services/inputflinger/dispatcher/InputDispatcher.h b/services/inputflinger/dispatcher/InputDispatcher.h
index 24e36ae..78cbf1e 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.h
+++ b/services/inputflinger/dispatcher/InputDispatcher.h
@@ -329,7 +329,7 @@
     std::chrono::nanoseconds mMonitorDispatchingTimeout GUARDED_BY(mLock);
 
     nsecs_t processAnrsLocked() REQUIRES(mLock);
-    nsecs_t processLatencyStatisticsLocked() REQUIRES(mLock);
+    void processLatencyStatisticsLocked() REQUIRES(mLock);
     std::chrono::nanoseconds getDispatchingTimeoutLocked(
             const std::shared_ptr<Connection>& connection) REQUIRES(mLock);