Enable LRS in local tests and fix LRS config generation bugs

Author: murgatroid99

packages/grpc-js-xds/src/load-balancer-lrs.ts

@@ -97,7 +97,7 @@ class LrsLoadBalancingConfig implements TypedLoadBalancingConfig {
     if (!('child_policy' in obj && Array.isArray(obj.child_policy))) {
       throw new Error('lrs config must have a child_policy array');
     }
-    const childConfig = selectLbConfigFromList(obj.config);
+    const childConfig = selectLbConfigFromList(obj.child_policy);
     if (!childConfig) {
       throw new Error('lrs config child_policy parsing failed');
     }

packages/grpc-js-xds/src/load-balancer-xds-cluster-resolver.ts

@@ -310,7 +310,8 @@ export class XdsClusterResolver implements LoadBalancer {
                 cluster_name: entry.discoveryMechanism.cluster,
                 eds_service_name: entry.discoveryMechanism.eds_service_name ?? '',
                 locality: {...localityObj.locality},
-                lrs_load_reporting_server: {...entry.discoveryMechanism.lrs_load_reporting_server}
+                lrs_load_reporting_server: {...entry.discoveryMechanism.lrs_load_reporting_server},
+                child_policy: endpointPickingPolicy
               }
             }];
           } else {

packages/grpc-js-xds/test/framework.ts

@@ -83,7 +83,8 @@ export class FakeEdsCluster implements FakeCluster {
       name: this.clusterName,
       type: 'EDS',
       eds_cluster_config: {eds_config: {ads: {}}, service_name: this.endpointName},
-      lb_policy: 'ROUND_ROBIN'
+      lb_policy: 'ROUND_ROBIN',
+      lrs_server: {self: {}}
     }
   }