Appointments: show first date with available time slots

[WilliamDEdwards]

Is your feature request related to a problem? Please describe.

The date picker defaults to today. However, there might not be any available time slots.

From a UX perspective, it doesn't make sense to require the user to then pick another date (at the risk of no time slots being available then either).

Describe the solution you'd like

The date picker should default to the first date with available time slots.

This doesn't require the user to, potentially multiple times and dropping out, pick another date manually.

Describe alternatives you've considered

No response

Additional context

No response