Update badge hiding to use visibility instead of display

[aentwist]

The reCAPTCHA docs FAQ specifies how to hide the reCAPTCHA badge.

Note: if you choose to hide the badge, please use

.grecaptcha-badge { visibility: hidden; }

I noticed that when using the option autoHideBadge: true, display: none is used instead.

.grecaptcha-badge {
  display: none !important;
}

If there was not a specific reason for this, then the rule should be updated to use visibility: hidden.