fix: change monaco-editor imports to type-only imports

[Federicorao]

Fixes #6545.

Change monaco-editor imports to type-only imports in MonacoCELEditor validation and completions files to prevent SSR crash. The error 'window is not defined' occurs because monaco-editor module accesses window during initialization. Two files in the MonacoCELEditor directory import from monaco-editor at module level but only use types. Changing these to type-only imports prevents the module from being loaded on the server side, fixing the SSR issue.

I ran the available lightweight check for the frontend change.

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