Remove xfail conditions for test_everflow_per_interface[ipv6-erspan_i…

[yanmo96]

…pv6-default] since it is duplicated with skip condition

Description of PR

Summary: Fixes # (issue)

Type of change

• [ ] Bug fix
• [ ] Testbed and Framework(new/improvement)
• [ ] New Test case
  • [ ] Skipped for non-supported platforms
• [ ] Test case improvement

Back port request

• [ ] 202205
• [ ] 202305
• [ ] 202311
• [ ] 202405
• [x] 202411
• [x] 202505
• [x] 202511

Approach

What is the motivation for this PR?

Remove duplicated xfail, since it should already been cover by the skip condition. So conditions can be more clear, less confusion and less maintenance.

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