fix(lfs): fixed LFS uploading on Windows because of opened file handler

[maybe-ilya]

Steps to reproduce:

1. Host soft-serve on Windows machine and create minimal working environment
2. Create empty repo on server
3. Prepare local repo with some LFS objects (object size doesn't matter) and track them. Or clone one of mine repos
4. Add remote url from step 2
5. Try to push

Actual result:
Temporary files from incomplete directory are blocked by t.storage.Open(os.Open) calls and can't be moved to new location.

Should fix #770

• I have read CONTRIBUTING.md.
• I have created a discussion that was approved by a maintainer (for new features).