[action] [PR:17889] Disable PFC-WD during PCBB and some wmk test improvements

[mssonicbld]

Description of PR

Summary:
During flaky test analysis of:

• qos/test_tunnel_qos_remap.py::test_pfc_watermark_extra_lossless_active
• qos/test_tunnel_qos_remap.py::test_pfc_watermark_extra_lossless_standby

Discovered that PFC-WD was enabled and being triggered during these tests. Added an auto-use fixture to disable PFC-WD and restore appropriately, similar to QOS SAI fixture.
Included the packet aging logic in case a relevant asic needs it going forward.

Changes:

1. Disable PFC-WD during all PCBB tests
2. Add a sleep after PFC-storm stop in PCBB tests to ensure packets are able to exit before further checks are performed.
3. Improve failure logging for above 2 tests.

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• New Test case
• Skipped for non-supported platforms
• Test case improvement

Back port request

• 202012
• 202205
• 202305
• 202311
• 202405
• 202411

Approach

What is the motivation for this PR?

How did you do it?

How did you verify/test it?

Validated: 1dfc735

• Both _active and _standby watermark tests pass on Cisco-8000 (3X executions)

Sample failure for new logging code:

E AssertionError: Watermark failures were found:
E For inner_dscp, outer_dscp, prio, queue = (3, 2, 3, 3):
E Failed to detect congestion due to PFC pause, failed check 0 > 10000

Any platform specific information?

Supported testbed topology if it's a new test case?

Documentation

[mssonicbld]

Original PR: #17889

[mssonicbld]

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