Increase sleep timeout of testNetworkFailedRollback_Phase3 (4/n)

My local tests show that sometimes testNetworkFailedRollback_Phase3
fails to reboot within 120s. Since it takes 120s to fail the health
check and trigger rollback, there is not much time left to finish
shutdown and begin reboot before finishing sleeping.

Let's generously give it 120 more seconds so shutdown and reboot have
enough time to take place.

Bug: 143999213
Test: atest StagedRollbackTest
Change-Id: Icf3a5583a906da312189a6d027a5c269e2fd8d46
diff --git a/tests/RollbackTest/RollbackTest/src/com/android/tests/rollback/StagedRollbackTest.java b/tests/RollbackTest/RollbackTest/src/com/android/tests/rollback/StagedRollbackTest.java
index 8f36b6e..06be5e2 100644
--- a/tests/RollbackTest/RollbackTest/src/com/android/tests/rollback/StagedRollbackTest.java
+++ b/tests/RollbackTest/RollbackTest/src/com/android/tests/rollback/StagedRollbackTest.java
@@ -251,11 +251,11 @@
 
     @Test
     public void testNetworkFailedRollback_Phase3() throws Exception {
-        // Sleep for > health check deadline
+        // Sleep for > health check deadline (120s to trigger rollback + 120s to reboot)
         // The device is expected to reboot during sleeping. This device method will fail and
         // the host will catch the assertion. If reboot doesn't happen, the host will fail the
         // assertion.
-        Thread.sleep(TimeUnit.SECONDS.toMillis(120));
+        Thread.sleep(TimeUnit.SECONDS.toMillis(240));
     }
 
     @Test