chore(config) rm Feature::CodexGitCommit (#22412)

## Summary
Removes the unused Feature::CodexGitCommit

## Testing
- [x] tests pass

codex-rs/Cargo.lock

@@ -1902,7 +1902,6 @@ dependencies = [
  "codex-feedback",
  "codex-file-search",
  "codex-file-watcher",
- "codex-git-attribution",
  "codex-git-utils",
  "codex-guardian",
  "codex-hooks",
@@ -2912,16 +2911,6 @@ dependencies = [
  "tracing",
 ]
 
-[[package]]
-name = "codex-git-attribution"
-version = "0.0.0"
-dependencies = [
- "codex-core",
- "codex-extension-api",
- "codex-features",
- "pretty_assertions",
-]
-
 [[package]]
 name = "codex-git-utils"
 version = "0.0.0"