Remove unused change behind the `refresh_authorizations_via_affected_projects_on_group_membership ` feature flag

What does this MR do and why?

The feature behind this feature flag is not going to be turned ON again because we had an incident when it was turned on the last time and we decided to not proceed with this plan further.

MR that introduced this change is !87071 (diffs)

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Related to #362204 (closed)