[6.16.z] Add a case for active_only box on the sync_status page

[Satellite-QE]

Cherrypick of PR: #17413

Problem Statement

There is a z-stream bug which needs to be automated, see the issue bellow for details.

TLDR: We need to verify the functionality of the Active only check-box on the Sync Status page.

Solution

This PR adds such UI test case.
It needs some Airgun changes too.

Related Issues

https://issues.redhat.com/browse/SAT-30291

PRT test Cases example

trigger: test-robottelo
pytest: tests/foreman/ui/test_sync.py -k test_sync_active_only
airgun: 1708

[LadislavVasina1]

trigger: test-robottelo
pytest: tests/foreman/ui/test_sync.py -k test_sync_active_only
airgun: 1720

[Satellite-QE]

PRT Result

Build Number: 9986
Build Status: UNSTABLE
PRT Comment: pytest tests/foreman/ui/test_sync.py -k test_sync_active_only --external-logging
Test Result : ========== 1 failed, 4 deselected, 13 warnings in 2479.90s (0:41:19) ===========

[LadislavVasina1]

trigger: test-robottelo
pytest: tests/foreman/ui/test_sync.py -k test_sync_active_only
airgun: 1720

[Satellite-QE]

PRT Result

Build Number: 9990
Build Status: SUCCESS
PRT Comment: pytest tests/foreman/ui/test_sync.py -k test_sync_active_only --external-logging
Test Result : =========== 1 passed, 4 deselected, 14 warnings in 803.01s (0:13:23) ===========