[Snappi] Fix duthost port mapping in multidut snappi tests (PFCWD, ECN)

[sdszhang]

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Description of PR

Summary: Fixes #13443

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?

Fix duthost and port mapping mismatch issue in multidut PFCWD and ECN test cases. PFC test cases will be changed in another PR to avoid large commit.

How did you do it?

Add 'duthost' into get_multidut_snappi_ports, so that we can retrieve duthost based on port information.

How did you verify/test it?

Test it manually. all PFCWD test cases can run successfully. There are test failures but are not related to this change.

Any platform specific information?

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

Documentation

[sdszhang]

@selldinesh @amitpawar12 @rraghav-cisco can you help to review this change? Thanks.

[sdszhang]

Discussed with Amit. Good to merge. @yejianquan Can you help to approve and merge this one? Thanks.

[mssonicbld]

Cherry-pick PR to 202405: https://github.com/sonic-net/sonic-mgmt/pull/13733