fix: Fetch state history in stream (#174)

Author: bracesproul

src/providers/Stream.tsx

@@ -84,6 +84,7 @@ const StreamSession = ({
     apiKey: apiKey ?? undefined,
     assistantId,
     threadId: threadId ?? null,
+    fetchStateHistory: true,
     onCustomEvent: (event, options) => {
       if (isUIMessage(event) || isRemoveUIMessage(event)) {
         options.mutate((prev) => {