(core) Fixing cursor position for filtered linked section.

Summary:
In a selector table, when a selected row is filtered out of view, linked widgets should update based on the newly selected row.
There were a few bugs that contributed to this wrong behavior:
- Gridview wasn't subscribing to the current row id, and the row with id 'new' was being converted to the first row
- Cursor was keeping track of the currently selected row id, it was hiding a problem behind the proper rowIndex
- Undo/redo somehow leveraged the wrong rowId from the cursor during the position restore.

The `No data` text was also changed to be more meaningful.

Test Plan: Added and updated.

Reviewers: georgegevoian

Reviewed By: georgegevoian

Differential Revision: https://phab.getgrist.com/D3937

app/client/components/CopySelection.ts

@@ -1,7 +1,6 @@
 import type {ViewFieldRec} from 'app/client/models/entities/ViewFieldRec';
 import type {CellValue} from 'app/common/DocActions';
-import type {TableData} from 'app/common/TableData';
-import type {UIRowId} from 'app/common/UIRowId';
+import type {TableData, UIRowId} from 'app/common/TableData';
 
 /**
  * The CopySelection class is an abstraction for a subset of currently selected cells.