lsp: Crash LSP server when pressing Ctrl-C
### Version

moe v0.3.0

Git hash: 5d0d5511b75ed7e175c597366aade76c28833edb
Build type: Release

### Environment

_No response_

### Category

Minor — The software basically does what it should do but there might be improvements.

### Steps to Reproduce

1. Start moe with LSP server
2. Press `Ctrl-C`

### Detailed Description

Need to block signals to child processes