chore: Make `tree-sitter` optional (#2450)

## Description

Make tree-sitter optional
## How to Test

```sh
cargo check -p gpui-component --no-default-features
cargo check -p gpui-component --features tree-sitter-languages
cargo check -p gpui-component --target wasm32-unknown-unknown
cargo check -p gpui-component --target wasm32-unknown-unknown --features tree-sitter-languages
cargo check --workspace
cargo test -p gpui-component --no-default-features
cargo test -p gpui-component --features tree-sitter-languages
```

## Checklist

- [x] I have read the [CONTRIBUTING](../CONTRIBUTING.md) document and
followed the guidelines.
- [x] Reviewed the changes in this PR and confirmed AI generated code
(If any) is accurate.
- [x] Passed `cargo run` for story tests related to the changes.
- [ ] Tested macOS, Windows and Linux platforms performance (if the
change is platform-specific)

---------

Co-authored-by: Jason Lee <huacnlee@gmail.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>