Fix onboarding OAuth callback glitch (#1079)

components/integrations/ConnectIntegrations.tsx

@@ -1,3 +1,4 @@
+import type { IntegrationOAuthCallbackState } from "pages/api/integrations/types";
 import { useState } from "react";
 import { useMutation } from "react-query";
 
@@ -13,8 +14,14 @@ export default function ConnectIntegration(props: {
 }) {
   const { type } = props;
   const [isLoading, setIsLoading] = useState(false);
+
   const mutation = useMutation(async () => {
-    const res = await fetch("/api/integrations/" + type.replace("_", "") + "/add");
+    const state: IntegrationOAuthCallbackState = {
+      returnTo: location.pathname + location.search,
+    };
+    const stateStr = encodeURIComponent(JSON.stringify(state));
+    const searchParams = `?state=${stateStr}`;
+    const res = await fetch("/api/integrations/" + type.replace("_", "") + "/add" + searchParams);
     if (!res.ok) {
       throw new Error("Something went wrong");
     }