Reverts zed-industries/zed#31399

I found that in some cases, Zed will panic when using `editor: open
selections in multibuffer` if the selection is reversed. It doesn't
happen in most cases that I've tested, but in some strange edge cases
(that I dont fully understand ATM), it does. I'm reverting for now, as
the previous behavior is better than a panic, but will re-implement this
fix to preserving selection directions in a new PR with comprehensive
testing

Release Notes:

- N/A