[6.16.z] Set DNF proxy for IPv6 runs

[Satellite-QE]

Cherrypick of PR: #16274

Problem Statement

DNF on the IPv6-only Satellite host can not download metadata as the download mirror/host has only A DNS record.

Proxy setting for DNF is being set in the enable_satellite_or_capsule_module_for_rhel8 method. However, this method executes its steps only on RHEL 8, as is stated in its name.

Setting proxy for DNF needs to be moved elsewhere.

Solution

Remove setting DNF proxy from enable_satellite_or_capsule_module_for_rhel8 and move it to a separate method. Call this method from Satellite.register_contenthost method right after we enable the proxy for subscription-manager.

Related Issues

SAT-27846

[Satellite-QE]

trigger: test-robottelo
pytest: -m build_sanity
env:
    ROBOTTELO_server__is_ipv6: true
    ROBOTTELO_server__version__rhel_version: 9
    BROKER_host_ipv6: true
    BROKER_host_ipv4_fallback: false

[Satellite-QE]

PRT Result

Build Number: 8537
Build Status: UNSTABLE
PRT Comment: pytest -m build_sanity --external-logging
Test Result : ======== 5563 deselected, 5760 warnings, 13 errors in 255.48s (0:04:15) ========

[Gauravtalreja1]

ACK, I think this can be merged without PRT as @ogajduse mentioned it works locally