Prevent randomized end time from being zero-offset

Author: Max Hniebergall

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/calendars/ScheduledEventTests.java

@@ -207,7 +207,7 @@ private void validateScheduledEventSuccessfulBuild(
         String description = randomAlphaOfLength(10);
         String calendarId = randomAlphaOfLength(10);
         Instant startTime = Instant.ofEpochMilli(Instant.now().toEpochMilli());
-        Instant endTime = startTime.plusSeconds(randomInt(3600));
+        Instant endTime = startTime.plusSeconds(randomIntBetween(1, 3600));
 
         ScheduledEvent.Builder builder = new ScheduledEvent.Builder().description(description)
             .calendarId(calendarId)