[action] [PR:15314] Stabilize pfcwd warm-reboot test on Mellanox platform

[mssonicbld]

Description of PR

Summary:
test_pfcwd_wb is flaky on Mellanox platform because PFCWD is not triggered as expected. The error is as below.

tests.common.plugins.loganalyzer.loganalyzer.LogAnalyzerError: match: 0
expected_match: 0
expected_missing_match: 1

Expected Messages that are missing:
.* detected PFC storm .*

The failure is because the pfc_gen.py script running on leaf-fanout can't generate continuous PFC pause to trigger PFCWD on DUT.
For each lossless queue, a separated pfc_gen.py will be running on leaf-fanout. If two_queues is true, then there will be two processes running for each port in test. Due to job schedule, it's not guaranteed that all processes can generate continuous PFC pause to trigger PFCWD.
To workaround the issue, the PR set two_queues to False for Mellanox platform if leaf-fanout is running EOS.

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• Test case(new/improvement)

Back port request

• 202012
• 202205
• 202305
• 202311
• 202405

Approach

What is the motivation for this PR?

This PR is to stabilize test_pfcwd_wb by limiting queue number to 1 on Mellanox platform if leaf-fanout is running EOS.

How did you do it?

Update fixture two_queues.

How did you verify/test it?

The change is verified on a Mellanox-SN2700 testbed. Test can pass after the change.

collected 3 items 

pfcwd/test_pfcwd_warm_reboot.py::TestPfcwdWb::test_pfcwd_wb[no_storm-str2-msn2700-spy-1] 
PASSED [ 33%]
pfcwd/test_pfcwd_warm_reboot.py::TestPfcwdWb::test_pfcwd_wb[storm-str2-msn2700-spy-1] 
PASSED [ 66%] 

Any platform specific information?

Mellanox platform specific.

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

Not a new test.

Documentation

[mssonicbld]

/azp run

[mssonicbld]

Original PR: #15314

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