core.sharedrepository=1 causes invalid permissions in generated files

**Describe the bug**
In the `setPermissions` function in `cmd_unix.go`, it mistakes the value of '1' as being an octal file mode instead of it's intended value of true. This causes the backend struct to have a umask of 776 and as a result all files pushed to the server via LFS will end up with an object file with the permissions `001` / `--------x`.

**Setup**
Please complete the following information along with version numbers, if applicable.
- OS [Ubuntu 22.04 LTS]
- Shell [bash]

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**To Reproduce**
Steps to reproduce the behavior:
1. Make a shared git repo using the command `git init --bare --shared`. (*You can manually check the git config for the repo to ensure that `core.sharedrepository=1`. It may not be for you, but it did for me, which triggered the bug.*)
2. Initialize git-lfs using `git lfs install`
3. Add `git-lfs-transfer` to the PATH
4. Clone the repo somewhere else using ssh `git clone ssh://server:/path/to/myrepo.git`
5. Add a file to the repo and tell `git-lfs` to track it.
6. Commit the file and push to the server.

**Expected behavior**
Since I used the `--shared` flag when creating the repo, and in `cmd_unix.go` the switch statement on the shared repository option includes an option for "true" which acts the same as "group", I would expect the permissions to be set to `660` which would mean the umask would be `117`.

Start in cmd_unix.go at the setPermissions function and reproduce the behavior with core.sharedrepository=1 in a shared repository. Verify that the true setting follows the same permission path as group and that generated LFS object files no longer receive 001 permissions; the expected umask is 117 for 660 files.

Written by the indexing model from the issue text.