Revert "Enforce approval rules based on attributes"

What does this MR do and why?

Revert "Merge branch '399117-enforce-security-policy-vulnerability_attributes-rules' into 'master'"

This reverts merge request !123965 (merged) to fix https://sentry.gitlab.net/gitlab/gitlabcom/issues/4169293/?query=is:unresolved

I prepared a bugfix for it in Fix vulnerability attributes access when nil (!126831 - closed), but it's safer to revert.

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