[Feature]: Allow shape mask for other types than frame
### What's the feature?

Hi there,

Thanks for the amazing tool!

Here is small feature request: i'm creating shape similar to Frame and i'd like to use shape mask, but it is locked now to type "frame" here https://github.com/tldraw/tldraw/blob/811fed79c8ad1c232a27f7b7a223224799e71e43/packages/editor/src/lib/editor/Editor.ts#L4414

Would appreciate if that can be configurable.

### Where would you like this feature?

The developer package

### Contact Details

_No response_

### Code of Conduct

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