Ignore Code Suggestions instance toggle setting

What does this MR do and why?

Ignore Code Suggestions instance toggle setting. This column will be removed with 16.11.

Follow-up to !145274 (merged), where we removed most of the uses of this column. The ones we missed I am removing now in this MR (mostly use in specs but also the column validation, which starts to fail once you ignore the column.)

See also https://gitlab.com/groups/gitlab-org/-/epics/12650

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Related to #440634