Update the `reset_required_approvals` method in the MergeRequest model to correctly reset approval counts for both v1 and v2 approval rule systems. Benefits: - Ensures approval counts are correctly reset when MR target branches change - Maintains backward compatibility with v1 approval rules - Prevents stale approval data when rules change due to branch updates - Supports the v2 approval rules architecture Requirements (validate these during implementation and adjust as needed): - Update `reset_required_approvals` method in `EE::MergeRequest` model - Use `approval_rules_for` helper to get the appropriate rule set (v1 or v2) - Reset `approvals_required` to 0 for all rules when target branch changes - Handle both v1 and v2 approval rule models correctly - Add specs for v1 and v2 scenarios - Ensure method works when `disable_overriding_approvers_per_merge_request` is enabled Reference: [v2 Approval Rules POC](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/222865) - See `ee/app/models/ee/merge_request.rb` lines 903-905