The PBVH usually is rebuild after a topology change, so it does not make
sense to keep the previous dynamic mesh preview vertex list. This may
cause a crash is the number of vertices of the new mesh (and preview) is
larger previous one. Now the list is deleted with the PBVH and a new one
will be generated using the new mesh when the cursor is updated.
Reviewed By: jbakker
Maniphest Tasks: T71712
Differential Revision: https://developer.blender.org/D6476
22f5edcf45