Summary:
Some edits to virtual tables (such as webhook lists) happen
via a route that was not yet handled. Actually Cyprien (the
original author) had handled this case but it got removed
because I didn't know what it was for :-). This brings back
support for edits by this route.
Test Plan: added a test
Reviewers: georgegevoian
Reviewed By: georgegevoian
Differential Revision: https://phab.getgrist.com/D3924