cosmwasm: update cw wormhole rust tests

[kakucodes]

Add Integration Tests for CW Wormhole Contract

This PR introduces comprehensive integration tests for the CW Wormhole contract using cw-multi-test, with a focus on end-to-end testing of core functionality.

Key Changes

• Implemented thorough integration tests for SubmitVAA logic covering:

  • Success paths with valid VAA submission and processing
  • Failure cases and error handling
  • Verification of query responses and state changes

• Enhanced test infrastructure:

  • Added helper methods for VAA generation and signing
  • Improved WormholeKeeper flexibility to support different guardian sets
  • Created local test environment setup utilities (potential candidate for future shared package)

Testing Approach

The tests take a high-level integration approach, simulating the full application and contract interactions with accurate state representation and signature verification. This provides stronger guarantees about the contract's behavior in realistic scenarios compared to unit tests alone.

Next Steps

Once we upgrade to a newer version of cosmwasm-std (and therefore cw-multi-test), we can:

• Remove #[ignored] tags from the currently skipped tests
• Add integration tests covering the PostMessage functionality

[joelsmith-2019]

Went over all code changes with Marc & everything's looking good.

[nik-suri]

LGTM. Verified that this change only affects non-functional testing code.