fix(popup-menu-web): update classname, remove screenshots

Author: rahmanunver

packages/pluggableWidgets/popup-menu-web/cypress-visual-screenshots/baseline/PopupMenu.spec-customPopUpMenuRight-chrome.png

@@ -8,7 +8,7 @@ exports[`Popup menu renders popup menu 1`] = `
     className="widget-popupmenu-root"
   >
     <div
-      className="popupmenu-menu popupmenu-position-bottom popup-portal"
+      className="popupmenu-menu popupmenu-position-bottom popup-portal mx-popup-menu"
       style={
         Object {
           "bottom": "initial",

packages/pluggableWidgets/popup-menu-web/cypress-visual-screenshots/baseline/PopupMenu.spec-customPopUpMenuTop-chrome.png

@@ -2,7 +2,7 @@
 
 exports[`Popup menu renders popup menu 1`] = `
 <div
-  className="popupmenu mx-popup-menu"
+  className="popupmenu"
   onClick={[Function]}
 >
   <div

packages/pluggableWidgets/popup-menu-web/cypress-visual-screenshots/baseline/PopupMenu.spec-customPopUpMenuTopRight-chrome.png

@@ -43,7 +43,12 @@ export function Menu(props: MenuProps): ReactElement {
             <div
                 ref={popupRef}
                 style={popupStyles}
-                className={classNames("popupmenu-menu", `popupmenu-position-${props.position}`, "popup-portal")}
+                className={classNames(
+                    "popupmenu-menu",
+                    `popupmenu-position-${props.position}`,
+                    "popup-portal",
+                    props.class
+                )}
             >
                 {menuOptions}
             </div>