fix: load active item from storage if present (#174)

We were doing this in the old redux model, but forgot to
implement since we moved the "active" state to the historySlice
rather than the stateSlice for easier manipulation and removing
thunks

server/app/src/state/historySlice.ts

@@ -24,8 +24,16 @@ const loadState = (): HistoryItem[] => {
   }
 };
 
+const loadActiveState = (): number | undefined => {
+  try {
+    return JSON.parse(localStorage.getItem("active")!);
+  } catch (err) {
+    return undefined;
+  }
+};
+
 const initialState: HistoryState = {
-  active: undefined,
+  active: loadActiveState(),
   items: loadState()
 };