Issue:
======
The network_namespace is not correctly handled in Automatic connection failover
feature, network_namespace is a replica property of the channel, that is, it
takes place on the replica network stack.

Solution:
=========
On the UDF functions, make the network_namespace optional and do not
use its values. When it is set by the user, raise a warning:
  The parameter network_namespace is reserved for future use. Please use the
  CHANGE REPLICATION SOURCE command to set channel network_namespace parameter.
Always use the network_namespace configured by CHANGE REPLICATION SOURCE command.

RB: 25476