[TASK] Bridge Registry pallet Integration for substrate chains

[salman01zp]

Overview

We need to fetch linked anchors from the bridge integration pallet for substrate-based chains just like we did for EVM here.

This will altogether remove linked anchors from the relayer configuration

Checklist

• [x] Fetch linked anchors from the bridge registry pallet
• [x] Update handlers to use linked anchors from the bridge registry pallet

[shekohex]

Closed by #447