message: Fix: trezor validators use `objectToErrorString` util
diff: import BN from 'bn.js';
  -import { assertTruth, validatorGenerator } from '../utils';
  +import { assertTruth, validatorGenerator, objectToErrorString } from '../utils';
  import { validators as messages } from './messages';
  import { PATH, MATCH, UNDEFINED, SPLITTER } from './defaults';
  @@ -195,14 +195,14 @@ export const bigNumberValidator = (bigNumber: any): boolean => {
  * It should be an instance of the BN Class
  */
  expression: BN.isBN(bigNumber),
  - message: `${bigNumberMessages.notBigNumber}: ${JSON.stringify(
  + message: `${bigNumberMessages.notBigNumber}: ${objectToErrorString(
  bigNumber,
  )}`,
  },
  ];
  return validatorGenerator(
  validationSequence,
  - `${bigNumberMessages.genericError}: ${JSON.stringify(bigNumber)}`,
  + `${bigNumberMessages.genericError}: ${objectToErrorString(bigNumber)}`,
  );
  };
  @@ -228,7 +228,7 @@ export const addressValidator = (address: any): boolean => {
  * It should be a string
  */
  expression: typeof address === 'string',
  - message: `${addressMessages.notStringSequence}: ${JSON.stringify(
  + message: `${addressMessages.notStringSequence}: ${objectToErrorString(
  address,
  ) || UNDEFINED}`,
  },
  @@ -272,7 +272,7 @@ export const hexSequenceValidator = (hexSequence: any): boolean => {
  * It should be a string
  */
  expression: typeof hexSequence === 'string',
  - message: `${hexSequenceMessages.notStringSequence}: ${JSON.stringify(
  + message: `${hexSequenceMessages.notStringSequence}: ${objectToErrorString(
  hexSequence,
  ) || UNDEFINED}`,
  },
  @@ -293,8 +293,7 @@ export const hexSequenceValidator = (hexSequence: any): boolean => {
  * idea to have "generalized" validator types
  */
  expression: hexSequence.length <= 1024,
  - message: `${hexSequenceMessages.tooBig}: ${JSON.stringify(hexSequence) ||
  - UNDEFINED}`,
  + message: `${hexSequenceMessages.tooBig}: ${hexSequence || UNDEFINED}`,
  },
  ];
  return validatorGenerator(
  @@ -324,7 +323,7 @@ export const messageValidator = (string: any): boolean => {
  * It should be a string
  */
  expression: typeof string === 'string',
  - message: `${messageMessages.notString}: ${JSON.stringify(string) ||
  + message: `${messageMessages.notString}: ${objectToErrorString(string) ||
  UNDEFINED}`,
  },
  {
  @@ -332,8 +331,7 @@ export const messageValidator = (string: any): boolean => {
  * It should be under (or equal to) 1024 Bytes in size
  */
  expression: string.length <= 1024,
  - message: `${messageMessages.tooBig}: ${JSON.stringify(string) ||
  - UNDEFINED}`,
  + message: `${messageMessages.tooBig}: ${string || UNDEFINED}`,
  },
  ];
  return validatorGenerator(
  