[FIX] web_editor: modal fullscreen is fullscreen

Depending on CSS surrounding the editor, the fullscreen component could
fail to set the editor fullscreen.

eg. if the editor is in a modal in a modal (ie. when editing a mail
template when adding an activity and creating a marketing automation
campaign) the fullscreen function would set it to 184px height away 30px
to the screen top.

With this change, `transform` css property is unset on parent elements
of the editor, this was causing the absolute editor to have an offset
parent that was not the body tag.

opw-1824605
closes #23682

addons/web_editor/static/src/less/web_editor.backend.less

@@ -52,9 +52,9 @@
         position: static !important;
         top: 0 !important;
         left: 0 !important;
-        overflow: visible !important;
         width: auto !important;
         overflow: hidden !important;
+        transform: none !important;
     }
 }