Fixing ScheduledEventTest generating same start and end time (#115877)

Co-authored-by: Elastic Machine <[email protected]>

Author: dan-rubinstein

muted-tests.yml

@@ -175,9 +175,6 @@ tests:
 - class: org.elasticsearch.xpack.spatial.search.GeoGridAggAndQueryConsistencyIT
   method: testGeoShapeGeoHex
   issue: https://github.com/elastic/elasticsearch/issues/115705
-- class: org.elasticsearch.xpack.core.ml.calendars.ScheduledEventTests
-  method: testBuild_SucceedsWithDefaultSkipResultAndSkipModelUpdatesValues
-  issue: https://github.com/elastic/elasticsearch/issues/115476
 - class: org.elasticsearch.xpack.test.rest.XPackRestIT
   method: test {p0=transform/transforms_start_stop/Verify start transform reuses destination index}
   issue: https://github.com/elastic/elasticsearch/issues/115808

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)