Update extensions marketplace metadata logic to respect Enterprise Group setting

MR: Extend extensions gallery metadata with enterpr... (!161740 - merged)

Description

After we add the relevant group db field, we should update the metadata_for_user function to return a new disabled reason enterprise_group_disabled.

Acceptance Criteria

• Relevant metadata_for_user function is updated taking into consideration EE concerns.
• The Workspaces and Web IDE clients won't blow up with the new disabled reason.