Afform - hide disabled contact types & entities from disabled components/extensions

[colemanw]

Overview

This cleans up and improves Afform's internal entity lookup so it won't show disabled entities.

Before

If Households are disabled, they still appear as Afform entities.
If CiviCase is disabled, it appears but with no label or icon (pending addition of Cases to Afform in a separate PR)

After

Entities from disabled contact types, extensions and components are hidden from the Afform UI.

[civibot]

(Standard links)

• If this is your first pull-request for CiviCRM, please browse CONTRIBUTING.md for information about the development and testing processes.
• If you are reviewing this pull-request, you may wish to consult the test sites and the Review Standards (long template, short template).

[seamuslee001]

This looks good to me merging