Contact page does not load proper com_user.profile XML

[Hackwar]

Pull Request for Issue #8120.

Summary of Changes

This adds in the right profile XML for the profile linked to a contact. See #8120 for a longer explanation.

Testing Instructions

1. Create or edit a contact and connect it with a user.
2. Edit the default.php layout of the contact view of com_contact and insert a var_dump($this->item);
3. Access the contact in the frontend and see that the $this->item->profile field contains an empty JForm object.
4. Apply the changes.
5. See that the JForm object now contains some data from the user.

[matrikular]

I have tested this item ✅ successfully on dce517b

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/16461.}

[richard67]

I have tested this item ✅ successfully on dce517b

Before patch:
... ["profile"]=> object(JForm)#444 (6) { ["data":protected]=> object(Joomla\Registry\Registry)#446 (3) { ["data":protected]=> object(stdClass)#453 (0) { } ...

After patch:
... ["profile"]=> object(JForm)#444 (6) { ["data":protected]=> object(Joomla\Registry\Registry)#446 (3) { ["data":protected]=> object(stdClass)#453 (3) { ["id"]=> string(2) ...

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/16461.}

[ghost]

RTC after two successful tests.