Drop Product Analytics cluster settings fields

What does this MR do and why?

These Product Analytics cluster settings fields are ignored since milestone 16.4. We now can drop these unused columns.

Note that these columns were dropped in a previous commit but reverted before deploying to production, since the columns were not ignored then.

How to set up and validate locally

1. Run migrations

   bundle exec rails db:migrate

2. Migrations should succeed

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.

Related to #421483 (closed)