[Feature]: Add functions for validating deposit prevouts

[djordon]

Feature - Add functions for validating deposit prevouts

1. Description

This is a subtask of #286.

There are a bunch of properties that need to be checked for each deposit input. Add functions that can help check these properties during validation.

1.1 Context & Purpose

Each bitcoin sweep transaction has 4 different parts that need validating:

1. deposit inputs,
2. withdrawal outputs,
3. signer TXO input,
4. signer UTXO outputs (one regular UTXO and one OP_RETURN TXO).

This ticket is for helping with (1).

2. Technical Details:

2.1 Acceptance Criteria:

• Add helper functions for validating deposit inputs.

3. Related Issues and Pull Requests (optional):

• relates to [Feature]: Validate bitcoin transaction sign requests #286.