[FIX] web_editor: ensure uploaded images in backend are not public

When uploading an image in the editor, we go through
`_attachment_create`, which sets the image to public if `res_model` is
`ir.ui.view` (the default if none was passed). Because of a wrong
reference to the editable DOM element (which contains the `res_model` as
data), when instantiating the media dialog, we were passing no
`res_model`. As a result, when saving an attachment, no `res_model` was
passed to `_attachment_create` and the attachment was made public.
Attachments in the backend should not be public and should be linked to
the proper model.

task-2759034

closes odoo/odoo#85132

X-original-commit: 5b664f0c04433091c3d6f85f245887d1808c308f
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>

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

@@ -1008,7 +1008,7 @@ const Wysiwyg = Widget.extend({
         const restoreSelection = preserveCursor(this.odooEditor.document);
 
         const $node = $(params.node);
-        const $editable = $(OdooEditorLib.closestElement(range.startContainer, '.o_editable'));
+        const $editable = $(this.odooEditor.editable);
         const model = $editable.data('oe-model');
         const field = $editable.data('oe-field');
         const type = $editable.data('oe-type');