Blender Git Loki

Fix [#26012] Import Collada: instance_node incorrectly handled
Reported by David Roy

When <instance_node>s where read, their transformation matrix got overwritten with the transform matrix
of their own node, not taking into account the parent node transformation. Instead of doing
that we now get the parent node transformation matrix and apply it to its own, and prevent
caller from overwriting this new transformation matrix.