[FIX] web_editor: Properly remove link tools frame

In mass mailing the link tools borders were not removed properly
because the element couldn't be found inside the Iframe with a $() selector.
Changed to use the `this.$link` of the `link_tool` class.

task-2634073

closes odoo/odoo#78416

X-original-commit: 4acdd17eba2a4175d1bec33397aebeadb1d5bc04
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>
Signed-off-by: Sébastien Geelen <sebgeelen@users.noreply.github.com>

addons/web_editor/static/src/js/wysiwyg/widgets/link_tools.js

@@ -53,7 +53,7 @@ const LinkTools = Link.extend({
         if (!this.el) {
             return this._super(...arguments);
         }
-        $('.oe_edited_link').removeClass('oe_edited_link');
+        this.$link.removeClass('oe_edited_link');
         const $contents = this.$link.contents();
         if (!this.$link.attr('href') && !this.colorCombinationClass) {
             $contents.unwrap();