fix: fix clear button on live-selects by clearing option on focus

[meagharty]

Summary of changes

Asana Ticket: No ticket, need to confirm desired behavior

• On focus, clear any dropdown results from previous searches
• Fixes clear button behavior
  • Pressing 'x' will now clear the previous search terms

Previously: if a user typed "Ale" and chose a value, then click back into the input (triggering phx-focus), the options stay filtered by "Ale" until they start typing

Now: if a user types "Ale" and chooses a value, then clicks back into the input, there are no options until they start typing

Reviewer Checklist

• Meets ticket's acceptance criteria
• Any new or changed functions have typespecs
• Tests were added for any new functionality (don't just rely on Codecov)
• This branch was deployed to the staging environment and is currently running with no unexpected increase in warnings, and no errors or crashes.