frontend: Fix missing getTimezones import in create-calendar-form

fixes #141

crates/frontend/public/assets/js/timezones-B0vBBzCP.mjs

@@ -0,0 +1,15 @@
+let timezonesPromise = null;
+async function getTimezones() {
+  timezonesPromise ||= new Promise(async (resolve, reject) => {
+    try {
+      let response = await fetch("/frontend/_timezones.json");
+      resolve(await response.json());
+    } catch (e) {
+      reject(e);
+    }
+  });
+  return await timezonesPromise;
+}
+export {
+  getTimezones as g
+};