Improvements to `ui_but_menu_add_path_operators` so that it properly
differentiates between files and directories even if the filepath is
not slash terminated. It will also not add the operators to the menu
if the filepath does not exist.
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Right-clicking on a pathname input we get a context menu that might contain "Open File Externally" and/or "Open Location Externally". But the first problem is that it does not check if this location exists, and we do have times where the paths do not exist yet. This PR makes this function a bool so that can return false if the files do not exist.
The second problem is that the function does not properly differentiate between a file path and directory path. For a directory path that is not slash terminated it will assume it is a file path. This PR actually checks the path (BLI_is_dir) to see if it really is a directory path.
Pull Request: https://projects.blender.org/blender/blender/pulls/113216
e44f500be8