floating-labels: remove aria-label in the select example (#35327)

While it is understood that this is just an example, the visible text (label) of "Works with selects" and the `aria-label="Floating label select example"` created a [WCAG 2.5.3 Label in name](https://www.w3.org/WAI/WCAG21/quickref/#label-in-name) failure.  

As the `aria-label` isn't necessary here since this `select` is already provided an accessible name by its `label` element, removing the unnecessary `aria-label` seems the best course of action as:
* removing it solves the WCAG issue 
* it removes the potential implication to developers that they'd even _need_ an `aria-label` here, let alone indirectly suggesting that it's ok for the visible text and accessible name to be out of alignment