Currently, `columnselect_action_keys` gets "raw" non-NLA-mapped keyframe
data via `ANIM_fcurve_keyframes_loop` with the `bezt_to_cfraelem` callback,
so the list of `CfraElem` contains frames in "local" FCurve space.
Later, this would be (rightfully) NLA-unmapped to "local/strip" time, because
this is what `ANIM_editkeyframes_ok(BEZT_OK_FRAME)` expects, it also only
compares "raw" `BezTriple` data.
But this only makes sense if we would store "global/scene" frame data in
`CfraElem` `cfra` already.
This is what we now do, let `bezt_to_cfraelem` perform the NLATIME_CONVERT_MAP
Pull Request: https://projects.blender.org/blender/blender/pulls/138937
d2ea328a6c