fix(installer): handle sudo shims that don't support -k flag (ohmyzsh#13651)

Related to ohmyzsh#13585

Co-authored-by: Daniel Bates <daniel@batesai.org>

Author: mcornella

tools/install.sh

@@ -473,7 +473,8 @@ EOF
   # be prompted for the password either way, so this shouldn't cause any issues.
   #
   if user_can_sudo; then
-    sudo -k chsh -s "$zsh" "$USER"  # -k forces the password prompt
+    sudo -k >/dev/null 2>&1         # -k forces the password prompt
+    sudo chsh -s "$zsh" "$USER"
   else
     chsh -s "$zsh" "$USER"          # run chsh normally
   fi