[Feature]: Add integration test for signing Stacks smart contracts

[djordon]

Feature - Add integration test for signing Stacks smart contracts

1. Description

1.1 Context & Purpose

We should add tests for making a contract call signed by the signer' multi-sig wallet. Because of the complexities of getting Nakamoto running, these integration tests do not need to run in CI.

3. Technical Details:

2.1 Acceptance Criteria:

• Add test(s) for submitting a stacks transaction.

4. Related Issues and Pull Requests (optional):

This is follow on work after #262 and #263.