* bug fix: Transaction.String() method panic

* Update dapps/valuetransfers/packages/transaction/transaction.go

Co-authored-by: Angelo Capossele <angelocapossele@gmail.com>

* Update dapps/valuetransfers/packages/transaction/transaction_test.go

Co-authored-by: Angelo Capossele <angelocapossele@gmail.com>

* Update dapps/valuetransfers/packages/transaction/transaction.go

Co-authored-by: Angelo Capossele <angelocapossele@gmail.com>

* Update dapps/valuetransfers/packages/transaction/transaction_test.go

Co-authored-by: Angelo Capossele <angelocapossele@gmail.com>

* Update dapps/valuetransfers/packages/transaction/transaction_test.go

Co-authored-by: Angelo Capossele <angelocapossele@gmail.com>

Co-authored-by: Angelo Capossele <angelocapossele@gmail.com>