Right now, we only refer to a port that needs to check for the proxy protocol as the "load balancer port" throughout our codebase (outside of mongod_main where we parse the proxyPort server parameter), even though it may also be referring to the proxyPort. This leads to confusion when reading the code. Improve the naming here to make it clearer that this actually checks for the load balancer port on mongos and the proxy port on mongod.