feat: allow tenant switching to be disabled

[ZANX3Y]

Description

This PR adds a switchableTenants() configuration method to the Panel builder, allowing developers to disable the tenant switcher, while keeping the tenant menu.

Visual changes

Functional changes

• Code style has been fixed by running the composer cs command.
• Changes have been tested to not break existing functionality.
• Documentation is up-to-date.

[People-Sea]

Thanks for the contribution!

Just curious - what's the use case for this? The existing tenantMenu(fn () => ...) can already conditionally hide the menu.

[danharrin]

Please rebase this commit on 4.x and change the target branch

[ZANX3Y]

Just curious - what's the use case for this? The existing tenantMenu(fn () => ...) can already conditionally hide the menu.

The tenantMenu() method affects the entire menu component.
This change provides finer control by letting you disable the tenant switching list, while keeping the menu functional for other actions (Profile, Billing, custom actions).
This is useful when there are other ways to access different tenants.