Dragging a non-Blend file onto the Blender executable currently
silently fails with Blender just aborting. With this PR any files used
as file argument will load Blender and show a warning if the file does
not exist or is not a blend file. Blend files that cannot be read are
treated as they are now.
Pull Request: https://projects.blender.org/blender/blender/pulls/139128
35d84e3336