Selectmenu: Properly parse value from options

Fixes #10684
(cherry picked from commit 809cc0f)

Conflicts:

	ui/selectmenu.js

Author: scottgonzalez

ui/selectmenu.js

@@ -594,7 +594,7 @@ return $.widget( "ui.selectmenu", {
 			data.push({
 				element: option,
 				index: index,
-				value: option.attr( "value" ),
+				value: option.val(),
 				label: option.text(),
 				optgroup: optgroup.attr( "label" ) || "",
 				disabled: optgroup.prop( "disabled" ) || option.prop( "disabled" )