Update bundletool am: 6e468659d4

Original change: https://android-review.googlesource.com/c/platform/prebuilts/bundletool/+/2784209

Change-Id: I09d32ad3c284ccc3db21c99d9c59c83433f3800e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>