Mark reporting_user role as deprecated

Author: legrego

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/security/authz/store/ReservedRolesStoreTests.java

@@ -2769,6 +2769,7 @@ public void testReportingUserRole() {
         RoleDescriptor roleDescriptor = ReservedRolesStore.roleDescriptor("reporting_user");
         assertNotNull(roleDescriptor);
         assertThat(roleDescriptor.getMetadata(), hasEntry("_reserved", true));
+        assertThat(roleDescriptor.getMetadata(), hasEntry("_deprecated", true));
 
         final String applicationName = "kibana-.kibana";