Handle attachment links more gracefully when expanding inline images

* lisp/org.el (org-display-inline-images): Introduce error-handling to
  ignore image display if the attachment link cannot be expanded for
  whatever reason.  For example if attachments are relative to the
  buffer, but the buffer is temporary and lacks filesystem location.

lisp/org.el

@@ -16722,9 +16722,9 @@ boundaries."
 	      (let ((file (if (equal "attachment" linktype)
                               (progn
                                 (require 'org-attach)
-                                (org-attach-expand path))
+				(ignore-errors (org-attach-expand path)))
                             (expand-file-name path))))
-		(when (file-exists-p file)
+		(when (and file (file-exists-p file))
 		  (let ((width
 			 ;; Apply `org-image-actual-width' specifications.
 			 (cond