[conditional_mark]: Skip unsupported FEC stats test on Tomahawk

[az-pz]

Description of PR

Summary:
Add a conditional skip for layer1/test_fec_error.py::test_verify_fec_stats_counters on Arista-7060CX-32S-D48C8, where Broadcom legacy Tomahawk SAI does not support the FEC_SYMBOL_ERR counter on 50G links.

This restores coverage of the platform limitation documented in #23936 for the test's layer1/ node ID; that PR added the equivalent condition for platform_tests/test_intf_fec.py.

Fixes # (issue): N/A

Type of change

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

Back port request

• 202311
• 202405
• 202411
• 202505
• 202511
• 202512
• 202605

Tracking issue/work item for backport/cherry-pick request (GitHub issue or Microsoft ADO): N/A
Failure type: day-one platform limitation

Tested branch

• master
• 202311
• 202405
• 202411
• 202505
• 202511
• 202512
• 202605
• N/A

Test result

master: Ran the layer1/test_fec_error.py test against a device with Arista-7060CX-32S-D48C8 HwSku. The test gets skipped.

=============================================== short test summary info ================================================
SKIPPED [1] layer1/test_fec_error.py: Broadcom TH does not support FEC_SYMBOL_ERR at 50G
=========================================== 1 skipped, 2 warnings in 44.27s ============================================

202605: The test gets skipped as expected.

=============================== short test summary info ================================
SKIPPED [1] layer1/test_fec_error.py: Broadcom TH does not support FEC_SYMBOL_ERR at 50G
=========================== 1 skipped, 2 warnings in 56.84s ============================

Approach

What is the motivation for this PR?

The FEC statistics test fails on Arista-7060CX-32S-D48C8 because Broadcom legacy Tomahawk SAI does not provide FEC_SYMBOL_ERR for 50G links. The existing conditional mark from #23936 only targets the former platform_tests/test_intf_fec.py node ID and therefore does not cover the test under layer1/test_fec_error.py.

How did you do it?

Added the equivalent conditional skip for layer1/test_fec_error.py::test_verify_fec_stats_counters, scoped to the affected HWSKU.

How did you verify/test it?

Ran the layer1/test_fec_error.py test against a device with Arista-7060CX-32S-D48C8 HwSku. The test gets skipped.

Any platform specific information?

This applies to Broadcom legacy Tomahawk on Arista-7060CX-32S-D48C8 at 50G.

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

N/A; this is not a new test case.

Documentation

N/A; this change only updates conditional test metadata.

MSFT ADO: 39182694

[azure-pipelines]

Azure Pipelines:
There may be pipelines that require an authorized user to comment /azp run to run.

[mssonicbld]

/azp run

[github-actions]

@StormLiangMS @wangxin @yxieca A user wants to merge changes to the conditional mark files into master. Please review.

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).

[Copilot]

Copilot review overview

🟢 Approval recommended

The condition matches the established platform-test exception and correctly targets the relocated test node.

Review effort: Balanced
Findings: None

What changed in this PR

Extends the existing Tomahawk FEC limitation handling from platform_tests to the equivalent layer1 test.

Changes:

• Skips the FEC statistics test on Arista-7060CX-32S-D48C8.
• Adds a section header for Layer 1 conditional marks.

File	Description
tests/​common/​plugins/​conditional_mark/​tests_mark_conditions.yaml	Adds the platform-specific conditional skip for the Layer 1 FEC test.

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[mssonicbld]

This PR has backport request label(s) for branch(es): 202605, but is missing required test information. Please make sure you tick the tested branch(es) in the Tested branch section and provide test evidence (e.g., 202605: <test result>) in the Test result section as well in your PR description.

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[mssonicbld]

The Tested branch section has been ticked and Test result is provided for branch(es): 202605. Added label(s): Tested for 202605 Branch.

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