94bbf297fc
`flex_xvert0` stored the Cartesian position of the vertices in `qpos0`. This array was unused, so it is now replaced with `flex_vert0`, which still contains the positions of the vertices, but normalized on the bounding box of the flex so that the coordinates are in `[0,1]^m->flex_dim`. This will be useful in the future for using different interpolation methods for computing flex deformations. PiperOrigin-RevId: 691779361 Change-Id: I5c4223103cd4558f4e268fe3e8d8177541e4754f