The point of sale customer display can no longer be customized from the backend to show custom advertising or similar content. This removes a confusing and frequently broken feature, making the customer display setup simpler and more reliable.

This commit removes feature allowing to customise the customer display which uses
to add an ad on the customer display.
Task-1944247

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This change removes an outdated Mexican fiscal position from the localization data after related enterprise changes. It helps keep the Mexico accounting configuration consistent and avoids offering a setup option that is no longer needed.

Related with https://github.com/odoo/enterprise/pull/5038

An unused upload wizard was removed from the Helpdesk and eLearning integration. This simplifies the product by removing an option that was not accessible from Helpdesk teams and discourages managing courses through the eLearning backend.

People shoudl not use the eLearning backend in order to manage their
courses. Moreover no link was present to allow uploading a slide
from helpdesk team.