M100: Disable CrostiniBullseyeUpgrade by default

This feature is being bumped to M101

Submit this to the *right* branch this time

(cherry picked from commit beb14ab)

Bug: 1217902
Change-Id: I55264f41fb6cb96a89dfc9a43402ffa1706ca756
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3473810
Reviewed-by: Timothy Loh <timloh@chromium.org>
Reviewed-by: David Munro <davidmunro@google.com>
Commit-Queue: Fergus Dall <sidereal@google.com>
Cr-Original-Commit-Position: refs/branch-heads/4895@{#5}
Cr-Original-Branched-From: 9a9b20d-refs/heads/main@{#972395}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3514806
Auto-Submit: Fergus Dall <sidereal@google.com>
Commit-Queue: David Munro <davidmunro@google.com>
Cr-Commit-Position: refs/branch-heads/4896@{#437}
Cr-Branched-From: 1f63ff4-refs/heads/main@{#972766}

ash/constants/ash_features.cc

@@ -302,7 +302,7 @@ const base::Feature kCroshSWA{"CroshSWA", base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Enables upgrading the crostini container to debian bullseye.
 const base::Feature kCrostiniBullseyeUpgrade{"CrostiniBullseyeUpgrade",
-                                             base::FEATURE_ENABLED_BY_DEFAULT};
+                                             base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Enables or disables Crostini Disk Resizing.
 const base::Feature kCrostiniDiskResizing{"CrostiniDiskResizing",