Change hardcoded PFC_STORM_TEST_PORT to choose from available interfaces

[justin-wong-ce]

Description of PR

Summary: Move logic that chooses PFC_STORM_TEST_PORT dynamically from 202311 to 202305

Type of change

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

Back port request

• [ ] 201911
• [ ] 202012
• [ ] 202205
• [x] 202305
• [ ] 202311

Approach

What is the motivation for this PR?

In 202305's tests/telemetry/events/swss_events.py, PFC_STORM_TEST_PORT is hardcoded to use Ethernet4, which may not be available for testing on some configurations.

How did you do it?

There already is logic on 202305 and master that dynamically selects the port for testing. Backporting that logic back to 202305.

How did you verify/test it?

Test machine without Ethernet4 can now continue running the test.

Any platform specific information?

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

Documentation

[zbud-msft]

This looks like a backport of https://github.com/sonic-net/sonic-mgmt/commit/a55ece70e0ff4e408e1255797e1449175a6a02c4, but we are missing the random.seed(), can you double check?

[StormLiangMS]

hi @justin-wong-ce could you check the comment and failed RP test?

[justin-wong-ce]

This looks like a backport of a55ece7, but we are missing the random.seed(), can you double check?

Sorry, it is indeed that backport. If you could backport that to 202305 as well that will be great. Will close PR after.

[justin-wong-ce]

hi @justin-wong-ce could you check the comment and failed RP test?

The checks seem to be fine, which test are you referring to?

[zbud-msft]

LGTM