[FIX] web_editor, website: fix columns mobile orders

This follows [commit 1], which introduced a way to separately reorder
columns on mobile and desktop.
This commit replaces the custom mobile order classes with the Bootstrap
`.order-x` classes.
It also ensures those orders are not used for mass mailing in case the
editor composes their email on a small window. The reorder would indeed
not have any effect for the end users in such a case.

[commit 1]: https://github.com/odoo/odoo/commit/710d000f1872fd99b41d52ec3d6923756bba7cba

task-3576046

closes odoo/odoo#140362

Signed-off-by: Arthur Detroux (ard) <ard@odoo.com>

addons/website/static/src/js/editor/snippets.options.js

@@ -4179,6 +4179,15 @@ options.registry.layout_column.include({
     },
 });
 
+options.registry.SnippetMove.include({
+    /**
+     * @override
+     */
+    _isMobile() {
+        return wUtils.isMobile(this);
+    },
+});
+
 export default {
     UrlPickerUserValueWidget: UrlPickerUserValueWidget,
     FontFamilyPickerUserValueWidget: FontFamilyPickerUserValueWidget,