Bug: MultisigTx PendingTx.UndoApplyUnconfirmed Not Applied

## Description

When applying transactions in block we first `undo` the `ApplyConfirmed()` logic via `UndoApplyUnconfirmed()` then `ApplyConfirmed()` 

In multisig we `can` have `PendingTransaction` in its body, which if present, require us to `Validate()` and `Apply(Un)Confirmed()) 

Current implementation missed the `UndoApplyUnconfirmed()` of the pending tx if exist.
