fix(legacy-plugin-chart-calendar): fix timestamp timezone in Calendar (#17664)

* fix(legacy-plugin-chart-calendar): fix timestamp timezone in Calendar

* Fix prop type

superset-frontend/plugins/legacy-plugin-chart-calendar/src/utils.ts

@@ -0,0 +1,30 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import { getTimeFormatter } from '@superset-ui/core';
+
+// Assume that given timestamp is UTC
+export const getFormattedUTCTime = (
+  ts: number | string,
+  timeFormat?: string,
+) => {
+  const date = new Date(ts);
+  const offset = date.getTimezoneOffset() * 60 * 1000;
+  return getTimeFormatter(timeFormat)(date.getTime() - offset);
+};