fix: missing internal types for transaction and block

[markin-io]

Issue being fixed or feature implemented

Fix adds missing declarations for the internal types of Block and Transaction, and also fixes a few inconsistencies in the Transaciton type itself

What was done?

How Has This Been Tested?

• SDK build and types test
• Wallet lib types test

Breaking Changes

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have made corresponding changes to the documentation

[shumkov]

👍