Disable flaky test from mediaroutertest

Bug: 292295557
Change-Id: I5ea4b4b2f6d7c732bbfaad2542538287fa41c9ff
Test: atest mediaroutertest

media/tests/MediaRouter/src/com/android/mediaroutertest/MediaRouter2ManagerTest.java

@@ -64,6 +64,7 @@ import com.android.compatibility.common.util.PollingCheck;
 
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Ignore;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
@@ -454,6 +455,7 @@ public class MediaRouter2ManagerTest {
         assertThat(onTransferFailedLatch.await(TIMEOUT_MS, TimeUnit.MILLISECONDS)).isTrue();
     }
 
+    @Ignore // TODO(b/291800179): Diagnose flakiness and re-enable.
     @Test
     public void testRouterRelease_managerGetRoutingSessions() throws Exception {
         CountDownLatch transferLatch = new CountDownLatch(1);