fix: New Arb Sepolia Chain Created for .arb.eth Domain Even if One Already Exists

[eduramme]

Description:

When creating a .arb.eth domain, the system always creates a new Arb Sepolia chain, even if the chain already exists for the domain. This behavior is incorrect and redundant, as the existing chain should be recognized instead of creating a new one.

Steps to Reproduce:

1. Attempt to create a new .arb.eth domain.
2. Observe that a new Arb Sepolia chain is created, even if a chain for the domain already exists.

Expected Behavior:

If an Arb Sepolia chain already exists for a .arb.eth domain, the system should not create a new one. Instead, it should recognize and use the existing chain.

Actual Behavior:

The system always creates a new Arb Sepolia chain, even if an existing one is already associated with the domain.

Acceptance Criteria:

• [ ] The system checks for an existing Arb Sepolia chain when creating a .arb.eth domain.
• [ ] A new chain is only created if no existing Arb Sepolia chain is found for the domain.

[eduramme]

@pikonha That's already solved, right?