[Demo] Leverage canAccess in CRM demo

[djhi]

Problem

React Admin 5.3.0 introduced a better access control mechanism but the CRM demo still uses the old permissions.

Solution

Convert the usage of permissions to canAccess.

How To Test

• Starts the demo

As an admin (the default)

• Check that you can access the users admin menu
• Check that you can access the sales pages
• Note an email of a "simple" sale

As the "simple" sale

• There is no Users menu item in the top right user menu dropdown
• Trying to access any sales URL by typing it directly in the browser address bar should redirect to the /access-denied pag

Additional Checks

• The PR targets master for a bugfix, or next for a feature
• The PR includes unit tests (if not possible, describe why)
• The PR includes one or several stories (if not possible, describe why)
• The documentation is up to date

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