Disable flaky AssistantOptInFlowTest.WAADisabledByPolicy

TBR=updowndota

Bug: 1013824
Change-Id: Ibbeb425fe2511f0dadaa93bb4dd3cbfde476877b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1857130Reviewed-by: David Roger <droger@chromium.org>
Commit-Queue: David Roger <droger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705491}

chrome/browser/chromeos/login/screens/assistant_optin_flow_screen_browsertest.cc

@@ -999,7 +999,8 @@ IN_PROC_BROWSER_TEST_F(AssistantOptInFlowTest,
   EXPECT_TRUE(prefs->GetBoolean(assistant::prefs::kAssistantContextEnabled));
 }
 
-IN_PROC_BROWSER_TEST_F(AssistantOptInFlowTest, WAADisabledByPolicy) {
+// This test is flaky. See https://crbug.com/1013824
+IN_PROC_BROWSER_TEST_F(AssistantOptInFlowTest, DISABLED_WAADisabledByPolicy) {
   assistant_settings_->set_consent_ui_flags(
       FakeAssistantSettings::CONSENT_UI_FLAG_WAA_DISABLED_BY_POLICY);