[Mellanox] Update qos sai tests for spc4 platform

[JibinBao]

Description of PR

1. update qos sai test for sn5400 refering to the two PRs below

• https://github.com/sonic-net/sonic-mgmt/pull/9583
• https://github.com/sonic-net/sonic-mgmt/pull/12848

2. To stabilize testQosSaiQSharedWatermark[single_asic-wm_q_shared_lossy], update margin from 4 to 5 for spc4

Summary: Fixes # (issue)

Type of change

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

Back port request

• [ ] 202012
• [ ] 202205
• [ ] 202305
• [ ] 202311
• [x] 202405

Approach

What is the motivation for this PR?

Update qos sai test for spc4 platform

How did you do it?

1. update qos sai test for sn5400
2. To stabilize testQosSaiQSharedWatermark[single_asic-wm_q_shared_lossy], update margin from 4 to 5 for spc4

How did you verify/test it?

Run qos tests on spc4 platform

Any platform specific information?

spc4

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

Documentation