(fix): don't print no citelinks if org-ref is not present (#714)

Change confusing behaviour where org-roam buffer prints "no citelinks"
even when org-ref is not present.

org-roam-buffer.el

@@ -116,32 +116,32 @@ When non-nil, the window will not be closed when deleting other windows."
 
 (defun org-roam-buffer--insert-citelinks ()
   "Insert citation backlinks for the current buffer."
-  (if-let* ((ref (with-temp-buffer
-                   (insert-buffer-substring org-roam-buffer--current)
-                   (org-roam--extract-ref)))
-            (org-ref-p (require 'org-ref nil t)) ; Ensure that org-ref is present
-            (key-backlinks (org-roam--get-backlinks (cdr ref)))
-            (grouped-backlinks (--group-by (nth 0 it) key-backlinks)))
-      (progn
-        (insert (let ((l (length key-backlinks)))
-                  (format "\n\n* %d %s\n"
-                          l (org-roam-buffer--pluralize "Cite backlink" l))))
-        (dolist (group grouped-backlinks)
-          (let ((file-from (car group))
-                (bls (cdr group)))
-            (insert (format "** [[file:%s][%s]]\n"
-                            file-from
-                            (org-roam--get-title-or-slug file-from)))
-            (dolist (backlink bls)
-              (pcase-let ((`(,file-from _ ,props) backlink))
-                (insert (propertize
-                         (s-trim (s-replace "\n" " "
-                                            (plist-get props :content)))
-                         'help-echo "mouse-1: visit backlinked note"
-                         'file-from file-from
-                         'file-from-point (plist-get props :point)))
-                (insert "\n\n"))))))
-    (insert "\n\n* No cite backlinks!")))
+  (when (require 'org-ref nil t) ;; Ensure that org-ref is present
+    (if-let* ((ref (with-temp-buffer
+                     (insert-buffer-substring org-roam-buffer--current)
+                     (org-roam--extract-ref)))
+              (key-backlinks (org-roam--get-backlinks (cdr ref)))
+              (grouped-backlinks (--group-by (nth 0 it) key-backlinks)))
+        (progn
+          (insert (let ((l (length key-backlinks)))
+                    (format "\n\n* %d %s\n"
+                            l (org-roam-buffer--pluralize "Cite backlink" l))))
+          (dolist (group grouped-backlinks)
+            (let ((file-from (car group))
+                  (bls (cdr group)))
+              (insert (format "** [[file:%s][%s]]\n"
+                              file-from
+                              (org-roam--get-title-or-slug file-from)))
+              (dolist (backlink bls)
+                (pcase-let ((`(,file-from _ ,props) backlink))
+                  (insert (propertize
+                           (s-trim (s-replace "\n" " "
+                                              (plist-get props :content)))
+                           'help-echo "mouse-1: visit backlinked note"
+                           'file-from file-from
+                           'file-from-point (plist-get props :point)))
+                  (insert "\n\n"))))))
+      (insert "\n\n* No cite backlinks!"))))
 
 (defun org-roam-buffer--insert-backlinks ()
   "Insert the org-roam-buffer backlinks string for the current buffer."