emacs-29 e5b0141b0d: Fix error editing multisession variables (bug#59710)

[Juanma Barranquero]

branch: emacs-29
commit e5b0141b0d7231426971763486b9cec0aac77a88
Author: Juanma Barranquero <lekktu@gmail.com>
Commit: Juanma Barranquero <lekktu@gmail.com>

    Fix error editing multisession variables (bug#59710)
    
    * lisp/emacs-lisp/multisession.el (multisession-edit-value):
    Do not use `bound-and-true-p' on a non-symbol.  This reverts
    commit bd586121ac21e046f60f75eeb0200866c38d6f9f.
---
 lisp/emacs-lisp/multisession.el | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lisp/emacs-lisp/multisession.el b/lisp/emacs-lisp/multisession.el
index 9d6e8c0d88..78d4137317 100644
--- a/lisp/emacs-lisp/multisession.el
+++ b/lisp/emacs-lisp/multisession.el
@@ -447,8 +447,9 @@ storage method to list."
   (let* ((object (or
                   ;; If the multisession variable already exists, use
                   ;; it (so that we update it).
-                  (and (intern-soft (cdr id))
-                       (bound-and-true-p (intern (cdr id))))
+                  (if-let (sym (intern-soft (cdr id)))
+                      (and (boundp sym) (symbol-value sym))
+                    nil)
                   ;; Create a new object.
                   (make-multisession
                    :package (car id)