Add various amounts of sanity checking for widget pinning
Add various amounts of sanity checking for widget pinning

This should also help https://github.com/vector-im/element-web/issues/15705 by either implicitly fixing the problem, causing chaos as described in the issue, or by forcing a crash to identify the problem more easily.
matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk,matrix-org/matrix-react-sdk