Fix query operation for qtModelEntityAttributeView.

Do not attempt to decode the search string into a bit vector and back again; if the conversion back to a string had been done with flagToSpecifierString() instead of flagSummary(), it would have worked for auxiliary surfaces, but instead we should just avoid converting at all; that will make the view proof against future changes to the query string format.

This also adds * as a valid model-entity specifier string (to mean the same as any).

Backport: release