feat: update middleware submodule to v1.0.3-testnet-slashing release

[MegaRedHand]

What Changed?

This PR updates the middleware submodule to the v1.0.3-testnet-slashing release. As part of this:

• adds the new RegistrationType prefix to the operator registration parameters (with an encoding test)
• adds the SlashingRegistryCoordinator and SocketRegistry to the bindings generated
• fixes a path typo on the bindings generation
• makes the SDK compatible with the new SlashingRegistryCoordinator (tests pending) by making the service manager address optional
• updates some type imports that were moved from contract interfaces to type-specific interfaces
• bumps solc pinned version to 0.8.27 on all contracts
• adds a LegacyRegistryCoordinator with additional functions to go back to M2 state

What's left for following PRs:

• testing of new contracts: SlashingRegistryCoordinator, and LegacyRegistryCoordinator with enabled operator sets and disabled M2 quorums.

Reviewer Checklist

• Code is well-documented
• Code adheres to Go naming conventions
• Code deprecates any old functionality before removing it