[Metrics] Disable FamilyUserMetricsProviderTest

FamilyUserMetricsProviderTest.UserCategory/* browser tests are causing
flaky failures. Disable the tests while looking for a fix.

Bug: 1144651
Change-Id: I92153b1b85db8970e5fa73c1d57fb9cc78b9ebb8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2514622
Commit-Queue: Toby Huang <tobyhuang@chromium.org>
Commit-Queue: Alexei Svitkine <asvitkine@chromium.org>
Auto-Submit: Toby Huang <tobyhuang@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823338}

chrome/browser/metrics/family_user_metrics_provider_browsertest.cc

@@ -117,7 +117,7 @@ class FamilyUserMetricsProviderTest
   base::test::ScopedFeatureList scoped_feature_list_;
 };
 
-IN_PROC_BROWSER_TEST_P(FamilyUserMetricsProviderTest, UserCategory) {
+IN_PROC_BROWSER_TEST_P(FamilyUserMetricsProviderTest, DISABLED_UserCategory) {
   base::HistogramTester histogram_tester;
   // Simulate calling ProvideCurrentSessionData() prior to logging in.
   // This call should return prematurely.