Remove unused ZoneId getter.

Signed-off-by: Finn Carroll <[email protected]>

Author: finnegancarroll

server/src/main/java/org/opensearch/search/DocValueFormat.java

@@ -314,10 +314,6 @@ public DateMathParser getDateMathParser() {
             return parser;
         }
 
-        public ZoneId getZoneId() {
-            return timeZone;
-        }
-
         @Override
         public String format(long value) {
             return formatter.format(resolution.toInstant(value).atZone(timeZone));