Use all_protected_branches in resolver

What does this MR do and why?

Use all_protected_branches in branch rules resolver to include group level protected branches in graphql responses.

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Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Enable the group_protected_branches feature flag
2. Create a group and a project within that group
3. Create a protected branch for the group
4. See the protected branch reflected under branch rules for the project (Settings -> Repository -> Branch Rules)

Related to #387649 (closed)