[ENHANCEMENT] Implement a Loading Test All function

[natn]

Printer model

• MK3S/+
• MK3
• MK2.5S
• MK2.5

Describe the enhancement

As a printer operator, I would like to be able to initiate a loading test for all filaments in the MMU3 without having to select each test individually.

Expected functionality

A menu item under Loading Test exists called Test All.
When the Test All option is selected, a filament test will be initiated sequentially for each MMU filament.
If a loading error occurs, the process stops and an error message indicating what filament failed to properly load will be displayed.

[3d-gussner]

@natn This is the Prusa firmware repository for the MK2.5/S and MK3/S/+ printers. Please close your issue here and open it in the https://github.com/prusa3d/Prusa-Firmware-Buddy which is for the MINI, MK3.5/S, MK3.9/S, MK4/S and XL.

I assume that you have a MK3.5/S, MK3.9/S or MK4/S with an MMU3 connected as the menu on the MK3S/+ Settings->Loading Test has the option "All".