bug: DWC 2.1.5 does not update active temperature

[c310]

DWC 2.1.5 + RRF 3.01-RC10

1. if i set some active temperature on extruder, let say 260
2. than i send .gcode for a print
3. that .gcode woudhave

M104 S290	; Raise extruder temp to profile requested

4. printer start heating up BUT active temperature remains 260... it will change to 290 only AFTER it has been reached,

in other words in the UI users will see temperature raising without visible reason for it.

@chrishamm proposed fix: update active temperature as soon as M104 received.

[chrishamm]

M104 is deprecated but still widely used by slicers. It is better to make the slicer generate G10 Pnnn Snnn instead. Since M104 waits for the pending moves to finish before it is processed, DWC may not be updated until the machine has stopped moving. There is not much I can do about it.