Clean up deps for file_finder, language_selector, task, rpc, storybook (#8353)

Following-up on #8330

Invocation
```bash
cargo-machete --with-metadata --skip-target-dir --fix
````

There is more stuff to fix, but it chokes on `async-lock`:
```
cargo-machete found the following unused dependencies in /x/Code/zed:
rpc -- /x/Code/zed/crates/rpc/Cargo.toml:
        async_lock
        prost_build
        serde_derive
Error: Dependency async_lock not found
```

Release Notes:
- N/A