Revert "Merge branch 'unresolved-threads-updates' into 'master'"

What does this MR do and why?

Describe in detail what your merge request does and why.

Reverts !97860 (merged) because it seems to be causing #376035 (comment 1120697204)

More details on why this happened in #376035 (comment 1120748458)

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How to set up and validate locally

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bundle exec rspec ee/spec/features/merge_request/user_merges_with_push_rules_spec.rb ee/spec/features/merge_request/user_views_blocked_merge_request_spec.rb spec/features/merge_request/user_merges_only_if_pipeline_succeeds_spec.rb spec/features/merge_request/user_sees_merge_widget_spec.rb spec/features/merge_request/user_accepts_merge_request_spec.rb spec/features/user_sees_revert_modal_spec.rb spec/features/merge_request/user_reverts_merge_request_spec.rb spec/features/merge_request/user_sees_merge_button_depending_on_unresolved_discussions_spec.rb against this branch should pass instead of fail like https://gitlab.com/gitlab-org/gitlab/-/jobs/3109717599

MR acceptance checklist

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