trezor-connect: Make refTxs param of SignTransaction optional
trezor-connect: Make refTxs param of SignTransaction optional

markogresak/DefinitelyTyped,dsebastien/DefinitelyTyped,dsebastien/DefinitelyTyped,borisyankov/DefinitelyTyped,mcliment/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,borisyankov/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped