This fixes T102218, where baked f-curves would display incorrectly when normalized.
This bug was a result of the code making no effort to determine the y-range of baked f-curves, so it fell back to a default that looked horrible.
I've added specific handling for finding the y-range of each f-curve (I extracted this functionality out to a new function, `fcurve_scene_coord_range_get`, for organization purposes). In addition, a minor optimization was made to eliminate redundant range-checks when in preview range mode.
{F13838304}
Reviewed By: sybren
Maniphest Tasks: T102218
Differential Revision: https://developer.blender.org/D16363