message: FormField: update disabled styles to match design
diff: border-color: var(--field_valid_border);
  }
  -.FormField--disabled .FormField__border {
  +.FormField--disabled {
  opacity: .4;
  + cursor: default;
  + pointer-events: none;
  }
  .FormField:not(.FormField--disabled) .FormField__border--hover {
  