[Accessibility] Duplicated and unnecessary text for voice in card form. v6.19

[captador]

Describe the bug
Slightly annoying issues of unnecessary texts for text-to-voice

1. Title of card form iframes contain a word Iframe which is not useful for text reader.

<iframe src="https://checkoutshopper-test.adyen.com/checkoutshopper/securedfields/test_6XQDRBGEDZBWVDHBCQ3XAROEKM6I3GRB/5.5.3/securedFields.html?type=card&amp;d=aHR0cHM6Ly9wYXltZW50LWRldi5zc2MtZGV2LnMtY2xvdWQuZmk=" class="js-iframe" title="Iframe for card number" allowtransparency="true" referrerpolicy="origin"><p>Your browser does not support iframes.</p></iframe>

2. Similarly icons in those card form fields could be hidden from reader. Those elements are just visual hints

<img alt="card" src="https://checkoutshopper-test.cdn.adyen.com/checkoutshopper/images/logos/nocard.svg" class="adyen-checkout-card-input__icon adyen-checkout__card__cardNumber__brandIcon">

Additional context

• "@adyen/adyen-web": "6.19.0"

[m1aw]

Hey @captador

1. This change has already been planned, and we will roll it out together with some other small a11y fixes.

2. Again we have gotten feedback on this topic too. At the moment we don't consider this to be only visual hints, but part of the content as it signifies what brands are available during checkout. This behaviour has been validated multiple times with our a11y partner so we don't want change it to be decorative.
   What we are planning in the future is change it from multiple images to a long label or list associated with the input field.

Happy to hear what you think of those changes.