[FIX] web_editor: fix gallery blocking the editor after image reordering

When snippets deeply alter the DOM (e.g. image reordering in gallery),
the related option might be destroyed since they are referencing old
DOM. If such a case occurred, the destroyed option was still waiting for
an option update response by the editor before being considered as
finished... which then never occurred and blocked the editor.

closes odoo/odoo#44998

X-original-commit: 9eeea4c4107dc15984c475582d5ee58a17cd2568
Signed-off-by: Quentin Smetz (qsm) <qsm@odoo.com>