Add valid labels for search button and input fields (a11y issue)

[batpigandme]

Both the collapsed and expanded search features (the button, and then the input field) currently have aria-labelledby properties set that reference an element that doesn't exist (and, thus, they have no label)

<div class="aa-Autocomplete" role="combobox" aria-expanded="false" aria-haspopup="listbox" aria-labelledby="autocomplete-0-label">
<button class="aa-DetachedSearchButton">
...
</button>
</div>

There are three associated accessibility issues I get related to the search:

1. ARIA input fields must have an accessible name
   Element: <div class="aa-Autocomplete" role="combobox" aria-expanded="false" aria-haspopup="listbox" aria-labelledby="autocomplete-0-label">
2. Buttons must have discernible text
   Element: <button class="aa-DetachedSearchButton">
3. ARIA attributes must conform to valid values
   Element: <div class="aa-Autocomplete" role="combobox" aria-expanded="false" aria-haspopup="listbox" aria-labelledby="autocomplete-0-label">
   Error: ARIA attribute element ID does not exist on the page: aria-labelledby="autocomplete-0-label"

The third presumably applies to the search input when opened on the element below:

<input class="aa-Input" aria-autocomplete="both" aria-labelledby="autocomplete-0-label" id="autocomplete-0-input" autocomplete="off" autocorrect="off" autocapitalize="off" enterkeyhint="search" spellcheck="false" placeholder="" maxlength="512" type="search">

As far as internationalization goes, it looks like the buttons have translation parameters in the Algolia docs.

Link to issue report from audit with axe: https://axe.deque.com/issues/7854d2a8-7632-43fd-98a7-ad22683ed4d5

[dragonstyle]

This is injected by our auto-complete library, so the simplest fix would be upstream- related issue:

algolia/autocomplete#963

For now, postponing and I'll work on trying to get fixed upstream.