Cat apis: Fix index creation time to use strict date format (elastic#32510)

With the move to java time, the default formatter used by toString on
ZonedDateTime uses optional components for least significant portions of
the date. This commit changes the cat indices api to use a strict date
time format, which will always output milliseconds, even if they are
zero.

closes elastic#32466

Author: rjernst

server/src/main/java/org/elasticsearch/rest/action/cat/RestIndicesAction.java

@@ -39,6 +39,7 @@
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.Table;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.time.DateFormatters;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
@@ -380,7 +381,8 @@ Table buildTable(RestRequest request, Index[] indices, ClusterHealthResponse res
             table.addCell(primaryStats.getDocs() == null ? null : primaryStats.getDocs().getDeleted());
 
             table.addCell(indexMetaData.getCreationDate());
-            table.addCell(ZonedDateTime.ofInstant(Instant.ofEpochMilli(indexMetaData.getCreationDate()), ZoneOffset.UTC));
+            ZonedDateTime creationTime = ZonedDateTime.ofInstant(Instant.ofEpochMilli(indexMetaData.getCreationDate()), ZoneOffset.UTC);
+            table.addCell(DateFormatters.forPattern("strict_date_time").format(creationTime));
 
             table.addCell(totalStats.getStore() == null ? null : totalStats.getStore().size());
             table.addCell(primaryStats.getStore() == null ? null : primaryStats.getStore().size());