[FIX] point_of_sale: Show warning when pricelist company missmatches

This commit ensure the pricelists are properly configured before launching a pos session.

Steps to reproduce:
- Have a V13 with point_of_sale
- Have minimum 2 companies A & B
- Select both companies in the company selector
- Go to Settings / General Settings
  - Point of Sale
    - Check Pricelists
- Go to Point of Sale
  - Open a pos.config PC
    - Set a Pricelist PL as Default Pricelist
- Go to Point of Sale / Products / Pricelists
  - Open PL
    - Set a company (must be different than PC)
- Go to Point of Sale
  - Click "New session" on PC
--> Traceback

In V13, the traceback shows as "Traceback not available"
As from V14, the traceback is shown properly

A variant would be to start the session before changing
the pricelist company then click on "Resume" on PC

closes odoo/odoo#78713

Signed-off-by: pimodoo <pimodoo@users.noreply.github.com>