Notebook cell and modal fix - follow up after Lucy's 14433. (#14457)

* Modal - added code to stop the keyboard event after it is handled. textCell and codeCell - onKey now fired on keydown.

* Moved stop method into the conditional with Escape key.

src/sql/workbench/browser/modal/modal.ts

@@ -472,6 +472,7 @@ export abstract class Modal extends Disposable implements IThemable {
 				if (event.equals(KeyCode.Enter)) {
 					this.onAccept(event);
 				} else if (event.equals(KeyCode.Escape)) {
+					DOM.EventHelper.stop(e, true);
 					this.onClose(event);
 				} else if (event.equals(KeyMod.Shift | KeyCode.Tab)) {
 					this.handleBackwardTab(e);