Added "waiting for screen off" flag to dump

Bug: 153923873
Test: test dump manually
Change-Id: I290ae190a00cff9ab1243ff7c45846f4421e8d2c

services/core/java/com/android/server/UiModeManagerService.java

@@ -777,6 +777,7 @@ final class UiModeManagerService extends SystemService {
                 pw.print(" ");
             }
             pw.println("");
+            pw.print(" waitScreenOff="); pw.print(mWaitForScreenOff);
             pw.print(" mComputedNightMode="); pw.print(mComputedNightMode);
             pw.print(" customStart="); pw.print(mCustomAutoNightModeStartMilliseconds);
             pw.print(" customEnd"); pw.print(mCustomAutoNightModeEndMilliseconds);