TPT 1880: Fixed issue with updating non-populated NodeBalancerNode

[ezilber-akamai-zz]

📝 Description

Previously, attempting to update a non-populated NodeBalancerNode would result in the update actually updating the resource silently. This change fixes the issue.

✔️ How to Test

pytest test

Note: Since this change deals with making updates to real resources as opposed to fixtures, it cannot be tested using mocks and must therefore be tested manually. To do this, first create a NodeBalancerNode in your Linode account if one does not already exist, and then run this python script and verify that the weight of the node was actually updated.

#!/usr/bin/env python3

from linode_api4 import LinodeClient
from linode_api4.objects import  NodeBalancerNode

client = LinodeClient(<personal_access_token>)

node = NodeBalancerNode(client, <node_id>, <config_id>, <nodebalancer_id>)

node.weight = 60

node.save()

Resolves #97