[Sheriff][Android] Disable flaky testCoreDirectActionInWebappActivity

Disables DirectActionAvailabilityTest#testCoreDirectActionInWebappActivity
as it has been flaking a lot.
Failed build link:
https://ci.chromium.org/p/chrome/builders/ci/test-n-phone/8984

TBR=szermatt@chromium.org

Bug: 1018183
Change-Id: I0812cff148432b0990a66411f94d9d2415531e56
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1879898Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Boris Sazonov <bsazonov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709446}

chrome/android/javatests/src/org/chromium/chrome/browser/directactions/DirectActionAvailabilityTest.java

@@ -18,6 +18,7 @@ import org.junit.Test;
 import org.junit.runner.RunWith;
 
 import org.chromium.base.test.util.CommandLineFlags;
+import org.chromium.base.test.util.DisabledTest;
 import org.chromium.base.test.util.Feature;
 import org.chromium.base.test.util.MinAndroidSdkLevel;
 import org.chromium.chrome.browser.ChromeActivity;
@@ -89,6 +90,7 @@ public class DirectActionAvailabilityTest {
     @Test
     @MediumTest
     @Feature({"DirectActions"})
+    @DisabledTest(message = "https://crbug.com/1018183")
     public void testCoreDirectActionInWebappActivity() throws Exception {
         mWebAppActivityTestRule.startWebappActivity();