Use `.sr-only` instead of text-hide technique

Created by: ysds

Fixes #27727 (closed)

I used the former, but which do you prefer?

<div class="spinner-border" role="status">
  <span class="sr-only">Loading...</span>
</div>

or

<span class="spinner-border" role="status" aria-hidden="true"></span>
<span class="sr-only">Loading...</span>

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