simplify some type checks by fixing graphql schema

web/src/components/events/EventContainer.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { useQueryState, parseAsStringLiteral } from "nuqs";
+import { useQueryState, parseAsStringLiteral, parseAsString } from "nuqs";
 import { EventItem } from "./EventItem";
 import { EventFilter } from "./EventFilter";
 import {
@@ -32,22 +32,12 @@ export const EventContainer = ({
   );
 
   const filterableCategories = eventCategories.filter((x) => x.showInFilters);
-  const filterableCategorySlugs: string[] = filterableCategories
-    .filter((x) => "slug" in x && typeof x.slug === "string")
-    .map((x) => x.slug);
-
-  const [category, setCategory] = useQueryState(
-    "category",
-    parseAsStringLiteral(filterableCategorySlugs).withDefault(null)
-  );
+  const [category, setCategory] = useQueryState("category", parseAsString);
 
   const filteredEvents = events.filter(
     (x) =>
       !category ||
-      x.categories
-        ?.filter((x) => x !== null)
-        .map((eventCategory: EventCategory) => eventCategory.slug)
-        .includes(category)
+      x.categories.map((eventCategory) => eventCategory.slug).includes(category)
   );
 
   return (