git: Fix panic in git2 due to empty repo paths (#42304)

Fixes ZED-1VR

Release Notes:

- Fixed sporadic panic in git features

crates/fs/src/fake_git_repo.rs

@@ -272,7 +272,7 @@ impl GitRepository for FakeGitRepository {
                     .ok()
                     .map(|content| String::from_utf8(content).unwrap())?;
                 let repo_path = RelPath::new(repo_path, PathStyle::local()).ok()?;
-                Some((repo_path.into(), (content, is_ignored)))
+                Some((RepoPath::from_rel_path(&repo_path), (content, is_ignored)))
             })
             .collect();
 
@@ -436,7 +436,7 @@ impl GitRepository for FakeGitRepository {
             state
                 .blames
                 .get(&path)
-                .with_context(|| format!("failed to get blame for {:?}", path.0))
+                .with_context(|| format!("failed to get blame for {:?}", path))
                 .cloned()
         })
     }

crates/fs/src/fs.rs

@@ -1792,7 +1792,8 @@ impl FakeFs {
             for (path, content) in workdir_contents {
                 use util::{paths::PathStyle, rel_path::RelPath};
 
-                let repo_path: RepoPath = RelPath::new(path.strip_prefix(&workdir_path).unwrap(), PathStyle::local()).unwrap().into();
+                let repo_path = RelPath::new(path.strip_prefix(&workdir_path).unwrap(), PathStyle::local()).unwrap();
+                let repo_path = RepoPath::from_rel_path(&repo_path);
                 let status = statuses
                     .iter()
                     .find_map(|(p, status)| (*p == repo_path.as_unix_str()).then_some(status));