Update monaco-editor to resolve DOMPurify CVE-2025-26791

We should upgrade the version of [monaco-editor](https://github.com/coder/coder/blob/cd1faffeff834d2c96653485a38d745e3bf5bb69/site/package.json#L96) from 0.53.0 to 0.55.0 once stable
https://github.com/coder/coder/blob/197b422a31fff71e3e99adc6cd031af769a994a6/site/package.json#L94

Reference:
https://github.com/microsoft/monaco-editor/issues/5078