Fix NPE getting a non existent memo from a schedule. (#2497)

Author: Quinn-With-Two-Ns

temporal-sdk/src/main/java/io/temporal/client/schedules/ScheduleDescription.java

@@ -112,8 +112,8 @@ public <T> Object getMemo(String key, Class<T> valueClass) {
 
   @Nullable
   public <T> T getMemo(String key, Class<T> valueClass, Type genericType) {
-    Payload memoPayload = this.memo.get(key);
-    if (memo == null) {
+    Payload memoPayload = memo.get(key);
+    if (memoPayload == null) {
       return null;
     }
     return dataConverter.fromPayload(memoPayload, valueClass, genericType);

temporal-sdk/src/test/java/io/temporal/client/schedules/ScheduleTest.java

@@ -110,6 +110,8 @@ public void createSchedule() {
     ScheduleHandle handle = client.createSchedule(scheduleId, schedule, options);
     ScheduleDescription description = handle.describe();
     Assert.assertEquals(scheduleId, description.getId());
+    // Verify the schedule description has the correct (i.e. no) memo
+    Assert.assertNull(description.getMemo("memokey1", String.class));
     // Try to create a schedule that already exists
     Assert.assertThrows(
         ScheduleAlreadyRunningException.class,