[dualtor_io] Add test_tor_switchover_impact test

[Ndancejic]

Test will send traffic from T1 -> server and perform switchover. It will then collect the logs and process the results to test_tor_switchover_impact.json

Any disruptions that break the threshold will cause test failure.

Description of PR

• Tests dualtor switchover impact
• Collects logs and processes results to test_tor_switchover_impact.json

Type of change

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

Back port request

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

Approach

What is the motivation for this PR?

Add metrics for dualtor switchover impact to test suite to track regressions

How did you do it?

added test test_tor_switchover_impact

How did you verify/test it?

ran on vms21-dual-t0-7050-3 dualtor testbed

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

active-standby dualtor