[Bug]: Faulty `open` mode breaks file uploads using the `ObjectWriter`.

[maxmynter]

What happened?

Changes made in commit 9d1c7f6 as part of #7903 break file uploads using the ObjectWriter:

ValueError: Must have exactly one of create/read/write/append mode and at most one plus

Python's open does not support sole binary mode.

Steps to Reproduce:

with open("testfile.txt", "b+"):
     pass

throws the error above.

Note that the mentioned commit appears in the 0.7.0 release.

Expected behavior

Don't throw and error

lakeFS version

latest

How lakeFS is installed

Docker

Affected clients

lakefs==0.7.0

Relevant log output

No response

Contact details

No response