Add "advanced" link that expands the FHIR server dropdown

[m-goggins]

As part of our work to collapse the demo and test user experiences into a single one, we need to make the FHIR servers available on the main query page (right now they are only available on the tester user journey).

When a user is on the query page, they should see an "Advanced" link/button that expands to reveal the FHIR server dropdown. These are the ideal Figma designs, but I think for the connectathon, we could just have another dropdown appear below the current Patient one. The dropdown should be labeled as the design.