(core) Don't show hidden tables in table data options when adding widgets

Summary:
As reported in https://grist.slack.com/archives/C069RUP71/p1655316194602829, when a table is hidden by ACL, it was still showing as a blank 'ghost' option to select data when adding a widget:

{F55498}

The fix is simply to return `true` from `isHiddenTable` for empty table IDs, which indicate a table hidden by ACL. `TableRec.isHidden` is supposed to match this so I updated it too, and I cleaned up a tiny bit of other related code.

Test Plan: Extended `nbrowser/AccessRules1.ts` to test the data options when adding widgets.

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D3530

app/client/models/SearchModel.ts

@@ -189,8 +189,6 @@ class FinderImpl implements IFinder {
     if ('data' === this._gristDoc.activeViewId.get()) {
       // Get all raw sections.
       const rawSections = this._gristDoc.docModel.visibleTables.peek()
-                              // Filter out those we don't have permissions to see (through ACL-tableId will be empty).
-                              .filter(t => Boolean(t.tableId.peek()))
                               // sort in order that is the same as on the raw data list page,
                               .sort((a, b) => nativeCompare(a.tableNameDef.peek(), b.tableNameDef.peek()))
                               // get rawViewSection,