Remove aria-label from links that open in a new window.

[alan-cole]

Summary

NOTE: This is a similar issue to #389.

At: https://github.com/civictheme/uikit/blob/main/components/01-atoms/link/link.twig#L77

an aria label of aria-label="Opens in a new tab" is set, which a screen reader would read out instead of the content within the link.

If removing this, the screen reader will still alert the user that the link opens in a new window, as..

<span class="ct-visually-hidden">(Opens in a new tab/window)</span>

...is included in the link if is_new_window is enabled. This is because text-icon.twig will include it.

Steps to reproduce

Go to https://uikit.civictheme.io/?path=/story/atoms-link--link and check "Opens in a new window".

Observed outcome

Screen reader will read out "Opens in a new tab" rather than "This should read out"

Expected outcome

Screen reader should read out " This should read out. Opens in a new tab"

[joshua-salsadigital]

Related Drupal issue: https://www.drupal.org/project/civictheme/issues/3488286