Add optional aria-label to search inputs.

[anemirovsky]

We had an accessibility auditor request that the input fields for search style dropdowns include an aria-label. I've reused the option from #43 to keep things consistent.

This pull request includes a

• [ ] Bug fix
• [x] New feature
• [ ] Translation

The following changes were made

• Adds an optional/configurable aria-label to search style inputs.

If this is related to an existing ticket, include a link to it as well. This is related to #43 and extends that to work for search style inputs.