Hello,

I've noticed that when I call #'tab-bar-new-tab while I'm in a
side-window that has siblings, I get an error from
#'window--sides-check, which happens when #'tab-bar-new-tab calls
#'delete-other-windows. Here's an example of my problem:

(progn
  (display-buffer-in-side-window (get-buffer-create "*hello*")
                                 '((side . right)
                                   (slot . 1)))
  (select-window
   (display-buffer-in-side-window (get-buffer-create "*world*")
                                  '((side . right)
                                    (slot . 2))))
  (tab-bar-new-tab))

The attached patch fixes this issue. Could it be applied to the emacs-29
branch?

Thanks!