bugfix: split fan/speed slider callbacks to fix gcode dispatch collision

[gmmcosta15]

• Feature
• Bug fix
• Code refactor
• Documentation

Description

• controlTab.on_slider_change: now handles fan_generic objects only, dispatches SET_FAN_SPEED.
• tunePage: add _on_speed_slider_change for print speed (M220); on_slider_change handles fan_generic only.
• printTab: minor cleanup following the callback split.

Motivation

When a fan_generic was named "speed", both controlTab and tunePage would dispatch conflicting gcodes (SET_FAN_SPEED and M220) on the same slider event. Splitting the callbacks eliminates the collision and ensures the correct gcode is always sent.

[HugoCLSC]

This needs more work.

There is no reason whatsoever where the slider should only emit a gcode for fan speed changes on objects that are [fan_generic]. Normal fans [fan] should have their speed changed using the slider as well.
So the slider needs to emit the appropriate gcode according to the fan object declaration.

Second thing, the gcode command M220 has nothing to do with fan speeds, that command sets the feedrate percentage . The appropriate command that i believe you were looking for is M106 SX, where X is an integer between [0-255].

Additionally, what happened with the ControlTab.py file, because the entire file is diff. I suggest just having just the actual changes.