remove --system from git config call as it fails on MacOS

```
❯ which git
/usr/bin/git

gitbutler ( missing-project) [$] via 
❯ git --version
git version 2.39.3 (Apple Git-146)

gitbutler ( missing-project) [$] via 
❯ git config -l --system --show-origin
fatal: unable to read config file '/etc/gitconfig': No such file or directory
```

Author: Byron

gix-path/src/env/git/mod.rs

@@ -89,7 +89,7 @@ pub(super) static EXE_INFO: Lazy<Option<BString>> = Lazy::new(|| {
             const CREATE_NO_WINDOW: u32 = 0x08000000;
             cmd.creation_flags(CREATE_NO_WINDOW);
         }
-        cmd.args(["config", "-l", "--system", "--show-origin"])
+        cmd.args(["config", "-l", "--show-origin"])
             .current_dir(env::temp_dir())
             .stdin(Stdio::null())
             .stderr(Stdio::null());