FormLabel: Allow InlineError to accept tabIndex attribute and override role attributes

[nichia]

Explore updating FormLabel InlineError component to enable more flexibility for overriding the default props (eg. remove role attribute) and accepting additional attributes like 'tabindex'.

To enable focus for keyboard users of the FormLabel error message, we have a use case for InlineError to include tabindex="-1" attribute and the removal of role attribute.
Removal of role="alert" is needed here since focus to this container will cause screen readers to announce it already.

Example:
<label class="ds-c-label ds-u-margin-bottom--3">
  <h2 class="ds-text-heading--xl ds-u-margin-bottom--1">
      Select all that apply to your household
  </h2>
  <span class="ds-c-field__error-message" id="ds-c-field__error-message_1" tabindex="-1">
    Choose at least one option to continue. If none of these options apply, select “None of these changes apply to me or anyone in my household.”
  </span>
</label>