[Probe] Decouple Homing from probing Session.

[viesturz]

The probe refactor is very helpful in making things more modular. However the Homing and Probing are stil tied together. This is a one-liner to make them independant. Allowing to have multiple probes and assigning homing to one.

Related: https://github.com/viesturz/klipper-toolchanger/commit/83873f82a9a64de35cafe698965efa2ef51f7adc