Blender Git Loki

Fix T92682: EEVEE motion blur crash with curve objects

After rBb9febb54a492, the evaluated mesh from a curve is now presented
to render engines as a separate mesh object, but some code still assumed
that a curve object itself could have an evaluated mesh. However, this is
still true for surface objects and metaballs, which don't
use geometry sets yet.

Differential Revision: https://developer.blender.org/D13272