Update src/darwin/Framework/CHIP/MTRDevice.mm

Co-authored-by: Boris Zbarsky <bzbarsky@apple.com>

Author: jtung-apple

src/darwin/Framework/CHIP/MTRDevice.mm

@@ -2195,7 +2195,7 @@ - (BOOL)_isCachePrimedWithInitialConfigurationData
     os_unfair_lock_assert_owner(&self->_lock);
 
     // Check if root node descriptor exists
-    NSDictionary * rootDescriptorPartsListDataValue = _readCache[[MTRAttributePath attributePathWithEndpointID:@(0) clusterID:@(MTRClusterIDTypeDescriptorID) attributeID:@(MTRAttributeIDTypeClusterDescriptorAttributePartsListID)]];
+    NSDictionary * rootDescriptorPartsListDataValue = _readCache[[MTRAttributePath attributePathWithEndpointID:@(kRootEndpointId) clusterID:@(MTRClusterIDTypeDescriptorID) attributeID:@(MTRAttributeIDTypeClusterDescriptorAttributePartsListID)]];
     if (!rootDescriptorPartsListDataValue || ![MTRArrayValueType isEqualToString:rootDescriptorPartsListDataValue[MTRTypeKey]]) {
         return NO;
     }