Remove ignore for dropped user profile fields

What does this MR do and why?

• Removes the ignore_columns for fields moved to the user_details table now that they have been dropped in !109019 (merged)
• Reverts test changes from !102351 (merged) that were required due to using ignore_columns

Important: this should be in milestone %15.10 or later.

How to set up and validate locally

1. Set a value for one of the attributes (I did linkedin) via avatar > Edit Profile.
2. Double check that the value was set correctly (either in the UI or via the Rails console).
3. Verify that the columns are not present on the User model:

[1] pry(main)> %i[linkedin twitter skype website_url location organization].map { |col| User.column_names.include? col }

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Closes to #206913 (closed)