Add onClosed event to ModelView dialogs (#17531)

* Add onClosed event to ModelView dialogs

* Use defined type

* Fix compile

* fix tests

* fix tests2

* Remove unused

src/sql/azdata.proposed.d.ts

@@ -579,6 +579,11 @@ declare module 'azdata' {
 
 	export namespace window {
 
+		/**
+		 * The reason that the dialog was closed
+		 */
+		export type CloseReason = 'close' | 'cancel' | 'ok';
+
 		export interface Dialog {
 			/**
 			 * Width of the dialog.
@@ -610,6 +615,11 @@ declare module 'azdata' {
 			 * Default is undefined.
 			 */
 			dialogProperties?: IDialogProperties;
+
+			/**
+			 * Fired when the dialog is closed for any reason. The value indicates the reason it was closed (such as 'ok' or 'cancel')
+			 */
+			onClosed: vscode.Event<CloseReason>;
 		}
 
 		export interface Wizard {