When pressing `I` in the viewport, the colors of the FCurve channels were no longer set correctly.
Caused by #113504
Fix by removing the flag that determined that in the first place,
and read straight from the user preferences. Then move the code
that sets the mode on the FCurve into the function that actually creates it.
For 99% of cases the code went to the user preference flag `AUTOKEY_FLAG_XYZ2RGB`
and if that was set, the `INSERTKEY_XYZ2RGB` would be set. The only case where this
was not from the user preferences was from custom keying sets.
There was an override flag for FCurve colors on custom keying sets.
I removed that with this patch since the use case is not apparent
and custom keying sets are hardly used.
Pull Request: https://projects.blender.org/blender/blender/pulls/115297
30b0c5b225