Mini buffer squeezed into one line when copying many files in `dired` mode

[ywwry66]

Thanks for maintaining this great software. Here is a bug I recently found.

Use dired mode to open a directory with 500 files with ivy mode on. Mark all the 500 files, press C (dired-do-copy), the ivy mini buffer will be squeezed into one line, making it very hard to navigate the target path. This doesn't happen when emacs is using full screen, but does when using half screen for example.