The option to buy SMS credits for Sign is now available from the Sign settings page instead of a role form that users rarely access. This makes the credit purchase action easier to find in the normal configuration flow.

In the role form view there is, currently, a button for adding sms credits to the account. However, the role form view is never accessed, since the tree view is directly editable. This PR removes the button from the form view and adds it to the settings page of sign.

task-2679754

This change updates internal approval and signing components so their styling can be passed in a more flexible way. It supports upcoming technical upgrades in the messaging area without changing the visible business workflow for users.

In preparation to use OWL v2 in discuss code

Task-2694196

community: https://github.com/odoo/odoo/pull/80060

Portal pages for appointments, helpdesk tickets, and signatures now show table headers once at the top instead of repeating them for every grouped section. This makes grouped lists easier to read and reduces visual clutter for users navigating portal records.

Currently, the header display above every group when the
group by is applied.

In this commit, we move the header with the fields labels at the top
of the table. 

task-2655707
Related PR: odoo/odoo#77408