fix: folders with names of unlinked entries are linked

[purpletennisball]

Summary

Fixes #989

When a unlinked entry has a folder with the same name:

• It can’t be deleted.
• It can’t be opened or revealed
• The thumbnail will show as unlinked
• File stats are hidden.
• Considered as unlinked in the Fix Unlinked Entries menu (which was the behaviour even before this PR)

Let me know if there is any changes you would like me to make :)

Tasks Completed

• Platforms Tested:
  • Windows x86
  • Windows ARM
  • macOS x86
  • macOS ARM
  • Linux x86
  • Linux ARM
• Tested For:
  • Basic functionality
  • PyInstaller executable

[CyanVoxel]

It looks like everything that's here fixes the specific areas they target, but there's still a few circumstances left that should be addressed before #989 should be considered closed:

• The relink process still does not check if a file is a folder when relinking
• Various methods in ThumbRenderer and PreviewThumb such as _image_thumb() will crash the program or throw a traceback if trying to render a thumbnail for a file that's been swapped with a folder of the same name, most notably _image_thumb() in my testing

[purpletennisball]

It looks like everything that's here fixes the specific areas they target, but there's still a few circumstances left that should be addressed before #989 should be considered closed:

• The relink process still does not check if a file is a folder when relinking

• Various methods in ThumbRenderer and PreviewThumb such as _image_thumb() will crash the program or throw a traceback if trying to render a thumbnail for a file that's been swapped with a folder of the same name, most notably _image_thumb() in my testing

I thought there may have been some stuff I missed. 🤔 I'll work on those changes as soon as I can. 👍