set_arguments action fail when ssh_proxy host does not have ansile_user specified

Summary

set_arguments action fail when ssh_proxy host does not have ansile_user specified

Steps to reproduce

• create environment with jump host
• on each host use same user as on client machine
• set ssh_proxy for one server to point other one
• call set_arguments action of ssh role
• ensure ansible_user is not set on ssh_proxy host

Expected behavior

everything should work correctly

Actual behavior

action will fail becuase ansible_user is not defined

Relevant logs and/or screenshots

N/A

Possible fixes

part using ansible_user should be protected with if statement.