WifiManager: Ignore void API calls with default values

When wifi service is not yet up, we throw a remote exception for API
calls which have void return. Change this to only throw a remote
exception when the input params have non-default values.

This takes care of cases where some other system modules resets wifi
params as a part of their initialization sequence (which will already be the
value when the wifi service comes up, so the calls are not useful)

Bug: 140076130
Bug: 139897982
Test: atest WifiManagerTest
Change-Id: If24d5ae52f1d39d2d99a860f3dc6c5f1860fd656