This update makes shared editor functionality easier to reuse across the website and backend by removing duplicate technical code and adjusting editor asset dependencies. It helps frontend features load the right editor tools more consistently, including point-of-sale appointment pages.

There are multiple duplicates of the `uuid` function, presumably because it is sometimes needed in frontend and was defined in `/web/views`. Update the usage of the function to import it from `/web/core`

Adapt `pos_appointment` manifest after the `html_editor.assets_editor` was updated to be importable with `assets_frontend`

task-4801746

This change updates internal tests for WhatsApp-related discussion channel behavior to stay aligned with recent platform changes. It helps maintain reliability and reduce the risk of regressions without changing day-to-day user workflows.

PR community: https://github.com/odoo/odoo/pull/212671
task-4829587