Media: Fix a jQuery Migrate warning for disabled buttons.

Under jQuery 4.0, disabling a media button or the image cropper's action button triggered a jQuery Migrate warning about the boolean `disabled` attribute. These buttons now toggle the `disabled` property instead, which removes the warning and keeps the behavior unchanged.

Developed in: #10661

Props audrasjb, azaozz, hbhalodia, neo2k23, wildworks.
See #64425.

git-svn-id: https://develop.svn.wordpress.org/trunk@62963 602fd350-edb4-49c9-b593-d223f7449a82

Author: t-hamano

src/js/media/controllers/cropper.js

@@ -116,7 +116,7 @@ Cropper = wp.media.controller.State.extend(/** @lends wp.media.controller.Croppe
 						selection.set({cropDetails: controller.state().imgSelect.getSelection()});
 
 						this.$el.text(l10n.cropping);
-						this.$el.attr('disabled', true);
+						this.$el.prop( 'disabled', true );
 
 						controller.state().doCrop( selection ).done( function( croppedImage ) {
 							controller.trigger('cropped', croppedImage );

src/js/media/views/button.js

@@ -64,7 +64,7 @@ var Button = wp.media.View.extend(/** @lends wp.media.view.Button.prototype */{
 		classes = _.uniq( classes.concat( this.options.classes ) );
 		this.el.className = classes.join(' ');
 
-		this.$el.attr( 'disabled', model.disabled );
+		this.$el.prop( 'disabled', model.disabled );
 		this.$el.text( this.model.get('text') );
 
 		return this;