ML extension - revised button component (#12674)

* Revert "Revert "ML extension updates  (#11817)" (#12645)"

This reverts commit 34a6200a47.

* Modified button template and renamed infoButton ElementRef

* fix rendering issue

* Minor code cleanup.

* add clean up previous button logic

Co-authored-by: Alan Ren <alanren@microsoft.com>

src/sql/azdata.proposed.d.ts

@@ -691,6 +691,24 @@ declare module 'azdata' {
 		 */
 		delete?: boolean;
 	}
+
+	export interface ButtonProperties {
+		/**
+		* Specifies whether to use expanded layout or not.
+		*/
+		buttonType?: ButtonType;
+		/**
+		* Description text to display inside button element.
+		*/
+		description?: string;
+	}
+
+	export enum ButtonType {
+		File = 'File',
+		Normal = 'Normal',
+		Informational = 'Informational'
+	}
+
 	export interface DiffEditorComponent {
 		/**
 		 * Title of editor