[com_fields] Fixing ACL inheritance for fields and fieldgroups

[Bakual]

Pull Request for Issue #13662.

Summary of Changes

When we added context support for fieldgroups, the assetname wasn't taken care of properly and thus ACL inheritance broke.

Testing Instructions

• Create some fieldgroups and assign some fields to it.
• Play with ACL settings. Settings should inherit from the component to fieldsgroups to fields. That means for example if you allow or deny the "Edit Custom Field Value" action in a field group, the fields in it should take that permission.

Documentation Changes Required

None

[joomdonation]

I have tested this item ✅ successfully on cf06d90

Tested permission inheritance from Component -> Field Group -> Field

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/13676.}

[ghost]

I have tested this item ✅ successfully on cf06d90

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/13676.}