Fix failing LicensingDocumentationIT test (#43533)

This PR brings corrections for cluster name after migrating to testclusters.
Not sure how this slipped trough the cracks when converting.

Closes #43504

Author: alpar-t

client/rest-high-level/src/test/java/org/elasticsearch/client/documentation/LicensingDocumentationIT.java

@@ -194,7 +194,7 @@ public void testGetLicense() throws Exception {
             //end::get-license-response
 
             assertThat(currentLicense, containsString("trial"));
-            assertThat(currentLicense, containsString("client_rest-high-level_integTestCluster"));
+            assertThat(currentLicense, containsString("integTest"));
         }
         {
             GetLicenseRequest request = new GetLicenseRequest();
@@ -233,7 +233,7 @@ public void onFailure(Exception e) {
             String currentLicense = response.getLicenseDefinition();
             assertThat(currentLicense, startsWith("{"));
             assertThat(currentLicense, containsString("trial"));
-            assertThat(currentLicense, containsString("client_rest-high-level_integTestCluster"));
+            assertThat(currentLicense, containsString("integTest"));
             assertThat(currentLicense, endsWith("}"));
         }
     }