fix: send nano tx

[andreabadesso]

Motivation

When creating a nano contract transaction, we might not have any inputs, as is the case in the initialize nano contract method.

Acceptance Criteria

• We shouldn't crash when a transaction has no inputs in txProposalCreate

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged
• Make sure either the unit tests and/or the QA tests are capable of testing the new features
• Make sure you do not include new dependencies in the project unless strictly necessary and do not include dev-dependencies as production ones. More dependencies increase the possibility of one of them being hijacked and affecting us.

The base branch was changed.