Add type for ControlsState.defaults

Partial<ControlsState> previously worked but has the side effect of
marking all keys as optional, which is not accurate and prone to cause
future type errors.

src/reducers/controls.ts

@@ -13,6 +13,7 @@ import { doesColorByHaveConfidence } from "../actions/recomputeReduxState";
 import { hasMultipleGridPanels } from "../actions/panelDisplay";
 
 export interface BasicControlsState {
+  defaults: Defaults
   panelsAvailable: string[]
   panelsToDisplay: string[]
   showTreeToo: boolean
@@ -36,11 +37,24 @@ export interface MeasurementsControlState {
 
 export interface ControlsState extends BasicControlsState, MeasurementsControlState {}
 
+interface Defaults {
+  distanceMeasure: string
+  layout: string
+  geoResolution: string
+  filters: Record<string, any>
+  filtersInFooter: any[]
+  colorBy: string
+  selectedBranchLabel: string
+  tipLabelKey: typeof strainSymbol
+  showTransmissionLines: boolean
+  sidebarOpen?: boolean
+}
+
 /* defaultState is a fn so that we can re-create it
 at any time, e.g. if we want to revert things (e.g. on dataset change)
 */
 export const getDefaultControlsState = () => {
-  const defaults: Partial<ControlsState> = {
+  const defaults: Defaults = {
     distanceMeasure: defaultDistanceMeasure,
     layout: defaultLayout,
     geoResolution: defaultGeoResolution,