Approvers group does not persist after adding it to the approval rules

What does this MR do and why?

• Contributes to #376289 (closed)
• Feature flag: #376331 (closed)

Problem

public_or_visible_to_user does not correctly resolves inherited permissions for subgroups.

For the structure,

Group A -> Group B
User has direct permissions to Group A

public_or_visible_to_user will return false for Group B.

Solution

Use accessible_to_user method to correctly apply the permission check.

How to set up and validate locally

See reproduction steps: #376289 (closed)

1. Enable feature flag

Feature.enable(:approval_rules_eligible_filter)

2. Create an approval rule with approval group sc_approvals_test/members/engineers
3. You should see two approvers in the list

FF off	FF on

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.