[Sheriff] Disable PassKitEGTest/testPassKitDownload due to flakiness

TBR=eugenebut@chromium.org

No-Try: True
Bug: 1109131
Change-Id: I07b8149e0f66af952206de6e0d5756a94df6661e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2317963Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Commit-Queue: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#791810}

ios/chrome/browser/ui/download/pass_kit_egtest.mm

@@ -122,7 +122,9 @@ std::unique_ptr<net::test_server::HttpResponse> GetResponse(
 
 // Tests that Chrome PassKit dialog is shown for sucessfully downloaded pkpass
 // file.
-- (void)testPassKitDownload {
+//
+// Flaky https://crbug.com/1109131.
+- (void)DISABLED_testPassKitDownload {
   if ([ChromeEarlGrey isIPadIdiom]) {
     EARL_GREY_TEST_SKIPPED(@"Wallet app is not supported on iPads.");
   }