[action] [PR:11160] [dualtor] use 'get_pdu_controller' to ensure same dut in test_power_off_reboot

[mssonicbld]

Description of PR

#8646 made a change in fixture 'pdu_controller' to always choose supervisor if device is chassis, for non-chassis it'll choose a random dut. PR 8646 will work in the same way for single-dut, but for dualtor, the randomly chosen dut could be different dut than the one under testing.

This PR call 'get_pdu_controller' to ensure pdu_controller is getting on the same dut.

There is no generic fix for this scenario that use "enum_supervisor_dut_hostname" for both tests and fixture pdu_controller, because platform_tests/conftest.py have a autouse fixture skip_on_simx that makes all platform tests use rand_one_dut_hostname.

Summary:
Fixes # (issue)

Type of change

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

Back port request

• 201911
• 202012
• 202205
• 202305

Approach

What is the motivation for this PR?

How did you do it?

How did you verify/test it?

Any platform specific information?

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

Documentation

[mssonicbld]

Original PR: #11160