CI: T2B1 hardware test on runner4 broken (uhubctl does not see the hub)

[coderabbitai]

Summary

The T2B1 hardware test runner4 is currently non-functional: uhubctl does not see the USB hub, so the device cannot be power-cycled and tests cannot run.

This is tracked as a FIXME comment in the CI workflow:

# FIXME runner4 with t2b1 does not work at the moment

As a workaround, T2B1 tests are currently routed to runner3 instead of the intended hw-t2b1 runner on runner4.

References

• PR: CI: hardware tests: add runners with T3B1, T3T1, T3W1 #6982
• Comment: CI: hardware tests: add runners with T3B1, T3T1, T3W1 #6982 (comment)

Requested by @obrusvit