Trying to visit files in magit-diff-paths output leads to wrong path

[gustav-b]

If I diff two files using the d p (magit-diff-paths) and then try to visit the files from the resulting diff buffer using RET (magit-diff-visit-file), this will fail because the attempted path is wrong.

Using Magit 20240320.2336 [>= 3.3.0.50-git], Transient 0.6.0, Git 2.44.0, Emacs 29.3, darwin

Steps to reproduce:

1. In a repos /tmp/foo, magit-diff-paths the files a.txt and b.txt
2. The resulting buffer will say Differences between /tmp/foo/a.txt and /tmp/foo/b.txt (correct)
3. Now press RET in this buffer to visit b.txt
   Expected behavior: /tmp/foo/b.txt is opened.
   Actual behavior: Emacs tries to open /tmp/foo/tmp/foo/b.txt instead: process-file: Setting current directory: No such file or directory, /tmp/foo/tmp/foo/