(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/ui/VisibleFieldsConfig.ts

@@ -217,10 +217,12 @@ export class VisibleFieldsConfig extends Disposable {
           primaryButton(
             dom.text((use) => t("Hide {{label}}", {label: use(this._fieldLabel)})),
             dom.on('click', () => this._removeSelectedFields()),
+            testId('visible-hide')
           ),
           basicButton(
             t("Clear"),
             dom.on('click', () => this._setVisibleCheckboxes(fieldsDraggable, false)),
+            testId('visible-clear')
           ),
           testId('visible-batch-buttons')
         ),
@@ -259,10 +261,12 @@ export class VisibleFieldsConfig extends Disposable {
             primaryButton(
               dom.text((use) => t("Show {{label}}", {label: use(this._fieldLabel)})),
               dom.on('click', () => this._addSelectedFields()),
+              testId('hidden-show')
             ),
             basicButton(
               t("Clear"),
               dom.on('click', () => this._setHiddenCheckboxes(hiddenFieldsDraggable, false)),
+              testId('hidden-clear')
             ),
             testId('hidden-batch-buttons')
           )