Fix T72148: OBJ import could fail with spaces in filenames

Thing here was that files could actually be loaded ('obj_image_load' has
smart code for this), but tokenizing the corresponding line afterwards
could still fail [would have part of a filename still in image_data
list].

Now also correct this 'image_data' list in case 'obj_image_load' found
images with filename spaces.

Maniphest Tasks: T72148

Differential Revision: https://developer.blender.org/D6358