Summary:
Grist should not prevent read-only viewers from opening cell editors since they usually provide much more information than is visible in a cell.
Every editor was enhanced with a read-only mode that provides the same information available for an editor but doesn't allow to change the underlying data.
Test Plan: Browser tests
Reviewers: dsagal
Reviewed By: dsagal
Differential Revision: https://phab.getgrist.com/D2842
698c9d4e40