term/{eshell,vterm}: remove already in * buffer check

Allows users to spawn additional eshell/vterm buffers, if they like.

modules/term/vterm/autoload.el

@@ -46,8 +46,6 @@ If prefix ARG is non-nil, cd into `default-directory' instead of project root."
   (interactive "P")
   (unless (fboundp 'module-load)
     (user-error "Your build of Emacs lacks dynamic modules support and cannot load vterm"))
-  (when (eq major-mode 'vterm-mode)
-    (user-error "Already in a vterm buffer"))
   (require 'vterm)
   ;; This hack forces vterm to redraw, fixing strange artefacting in the tty.
   (save-window-excursion