Verbatim reuse of packfiles completely disabled when `BTMP` chunk is missing
With 0fea6b73 (Merge branch 'tb/multi-pack-verbatim-reuse', 2024-01-12) Git has introduced a new mechanism that allows for multi-packfile verbatim reuse of deltified objects. This new mechanism makes use of a new BTMP
chunk that must exist for the mechanism to kick in. As this chunk has only been introduced with that series it is thus expected to not exist when upgrading to this Git version. Git doesn't gracefully handle the BTMP
chunk missing though and will complain, which results in user-visible errors when cloning a repository.
Instead, Git should fall back to use the preferred MIDX packfile.