fix: remove lock time verification

[karim-en]

This pull request makes a targeted change to the deposit validation logic in the Contract implementation. Specifically, it removes the requirement that a transaction's lock_time must be zero. This means transactions with a non-zero lock_time are now supported, which could allow for more flexible transaction types in the bridge contract.

Deposit validation update:

• Removed the check that required transaction.lock_time() to be zero, allowing transactions with non-zero lock_time values to be processed.