[M115][Branch Gardener]Disable flaky FencedFrameInThreatDetails test.

The test is flaking on Lacros builds. Disable it until a long term
solution for the test is figured out.

(cherry picked from commit 2a525ab)

Bug: 1445499
Change-Id: I1ee6d87924b0bc6b40414e9ff07530179ebb8e98
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4568531
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Liam Brady <lbrady@google.com>
Cr-Original-Commit-Position: refs/heads/main@{#1149741}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4598681
Auto-Submit: Elaine Chien <elainechien@chromium.org>
Owners-Override: Elaine Chien <elainechien@google.com>
Reviewed-by: Donn Denman <donnd@chromium.org>
Commit-Queue: Donn Denman <donnd@chromium.org>
Cr-Commit-Position: refs/branch-heads/5790@{#471}
Cr-Branched-From: 1d71a33-refs/heads/main@{#1148114}

chrome/browser/safe_browsing/safe_browsing_blocking_page_test.cc

@@ -3376,8 +3376,9 @@ IN_PROC_BROWSER_TEST_P(SafeBrowsingFencedFrameBrowserTest, UnsafeFencedFrame) {
 }
 
 // This test is modeled after IframeOptInAndReportThreatDetails above.
+// TODO(https://crbug.com/1445499): Flaky
 IN_PROC_BROWSER_TEST_P(SafeBrowsingFencedFrameBrowserTest,
-                       FencedFrameInThreatDetails) {
+                       DISABLED_FencedFrameInThreatDetails) {
   SetExtendedReportingPrefForTests(browser()->profile()->GetPrefs(), true);
   const bool expect_threat_details =
       SafeBrowsingBlockingPage::ShouldReportThreatDetails(GetThreatType());