[Gardener] Mark snap-fling-in-large-area.html as flaky

This test is flaky on Win11 Tests x64 builder.
i.e. https://ci.chromium.org/ui/p/chromium/builders/ci/Win11%20Tests%20x64/26610/overview

Bug: 380534434
Change-Id: I86a2d9f8dc6f627b378d5b7ce778ec2bfd8523a8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6056928
Commit-Queue: Nidhi Jaju <nidhijaju@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1389206}

third_party/blink/web_tests/TestExpectations

@@ -8678,3 +8678,6 @@ crbug.com/381085690 [ Win ] virtual/webnn-service-on-cpu/external/wpt/webnn/vali
 # Gardener 2024-11-27
 crbug.com/381142479 [ Linux ] virtual/view-transition-on-navigation/external/wpt/css/css-view-transitions/navigation/pagereveal-ctor.html [ Failure Pass ]
 crbug.com/378680890 [ Mac ] fast/peerconnection/RTCPeerConnection-many.html [ Pass Timeout ]
+
+# Gardener 2024-11-28
+crbug.com/380534434 [ Win11 ] external/wpt/css/css-scroll-snap/snap-fling-in-large-area.html [ Failure Pass Timeout ]