move incomplete filters out of dashboard store and into a dedicated piece of state

[briangregoryholmes]

This PR moves temporary/potential/incomplete filters (those that do not have dimension values) outside of the dashboard store.

This addresses a change in the runtime that happened in #3624 that requires the in field of a filter be a nonempty array.

[ericpgreen2]

Code looks good 👍

Approving, but one UXQA nit captured in this Jam to fix before merging:

• I add one filter.
• I start to add a subsequent filter and select a new dimension to filter on.
• The dimension values from the prior filter flash before rendering the dimension values of the new dimension.