Fix compatibility with Tramp 2.6.0.2 and above

With Tramp 2.6.0.2 and above, during `dired` completion, typing
"//ssh:" followed by "C-j" (ivy-alt-done) gives the error "Reading
directory: No such file or directory, /ssh:".  Previously the output
was a list of possible completions.

This fix (#3046) proposed by Tramp maintainer
Michael Albinus <[email protected]> in the following thread:
https://lists.gnu.org/r/tramp-devel/2023-03/msg00014.html
https://lists.gnu.org/r/tramp-devel/2024-05/msg00000.html

Copyright-paperwork-exempt: yes

Author: ywwry66

ivy.el

@@ -1067,6 +1067,10 @@ contains a single candidate.")
              (defvar tramp-completion-mode)
              (with-no-warnings
                (let* ((tramp-completion-mode t)
+                      ;; Alternative to `tramp-completion-mode' in newer Tramp.
+                      (non-essential t)
+                      ;; Non-nil changes completion since Tramp 2.6.0.2.
+                      (minibuffer-completing-file-name nil)
                       (file (expand-file-name
                              (if (> ivy--length 0) (ivy-state-current ivy-last) ivy-text)
                              ivy--directory)))