fix(s3): enable content md5 header even if user can't check it

[fbeauchamp]

Description

enable content md5 header, required by object lock in case user don't have enough authorization to check if object lock is enable or not

from
https://xcp-ng.org/forum/topic/7939/unable-to-connect-to-backblaze-b2/7?_=1700572613725
following : 796e2ab

user report it fixes the issue : https://xcp-ng.org/forum/post/67633

Checklist

• Commit
  • Title follows commit conventions
  • Reference the relevant issue (Fixes #007, See xoa-support#42, See https://...)
  • If bug fix, add Introduced by
• Changelog
  • If visible by XOA users, add changelog entry
  • Update "Packages to release" in CHANGELOG.unreleased.md
• PR
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  • If not finished or not tested, open as Draft