Let fetcher fails less from 503 am: 711f5e943f am: b8c38af9bc am: c5d65b9f42

Original change: https://android-review.googlesource.com/c/platform/tools/treble/+/2535284

Change-Id: I359833158164c7743028c865e17e45a53af2b633
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>