Make MultipleReferenceEditor content types configurable via props

[sbuys]

Currently this pulls from all content types via const allContentTypes = props.sdk.space.getCachedContentTypes();

This limits configurability of the field for use cases where we'd like to limit content types based on some other criteria (e.g. another field value)

[github-actions[bot]]

Marking issue as stale since there was no activity for 30 days