fix(elasticsearch): use correct latency metric names (#11175)

Fixes #11174

As per the issue details, this uses the correct metric names as described in [the documentation](https://docs.aws.amazon.com/elasticsearch-service/latest/developerguide/es-managedomains-cloudwatchmetrics.html).

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-elasticsearch/lib/domain.ts

@@ -1038,7 +1038,7 @@ abstract class DomainBase extends cdk.Resource implements IDomain {
    * @default p99 over 5 minutes
    */
   public metricSearchLatency(props?: MetricOptions): Metric {
-    return this.metric('SearchLatencyP99', { statistic: 'p99', ...props });
+    return this.metric('SearchLatency', { statistic: 'p99', ...props });
   }
 
   /**
@@ -1047,7 +1047,7 @@ abstract class DomainBase extends cdk.Resource implements IDomain {
    * @default p99 over 5 minutes
    */
   public metricIndexingLatency(props?: MetricOptions): Metric {
-    return this.metric('IndexingLatencyP99', { statistic: 'p99', ...props });
+    return this.metric('IndexingLatency', { statistic: 'p99', ...props });
   }
 
   private grant(

packages/@aws-cdk/aws-elasticsearch/test/domain.test.ts

@@ -394,15 +394,15 @@ describe('metrics', () => {
   test('Can use metricSearchLatency on an Elasticsearch Domain', () => {
     testMetric(
       (domain) => domain.metricSearchLatency(),
-      'SearchLatencyP99',
+      'SearchLatency',
       'p99',
     );
   });
 
   test('Can use metricIndexingLatency on an Elasticsearch Domain', () => {
     testMetric(
       (domain) => domain.metricIndexingLatency(),
-      'IndexingLatencyP99',
+      'IndexingLatency',
       'p99',
     );
   });