[FIX] web: set correct raw domain

Steps to reproduce:
- Activate debug mode
- Go to Sales and open a quotation (actually any form view from any
  module will do)
- Start Studio
- Select the "Confirm" button (or any of the top buttons)
- Check the "Set approval rules" box
- Edit the domain by clicking the 'filter' icon next to the 'trash' icon
- Add a condition. You can just keep the default one.
- Click save to save the domain.
- Again, click on the 'filter' icon.

You should see that the domain in the text editor is malformed.
Furthermore, should you change the domain in the text editor (let's say,
change 1 to 2) and hit save, an error message will pop saying the domain
is not properly formatted.

opw-3001622

closes odoo/odoo#106034

X-original-commit: 9535026e
Signed-off-by: Mathieu Duckerts-Antoine <dam@odoo.com>