org-export-expand-include-keyword: Drop unnecessary call to `save-match-data'

* lisp/ox.el (org-export-expand-include-keyword): Do not wrap
`org-element-at-point' into `save-match-data'.  The search data from
`re-search-forward' is unused in the code and `save-match-data' call
is costly.

lisp/ox.el

@@ -3401,7 +3401,7 @@ variables in include file names."
     (goto-char (point-min))
     (while (re-search-forward include-re nil t)
       (unless (org-in-commented-heading-p)
-        (let ((element (save-match-data (org-element-at-point))))
+        (let ((element (org-element-at-point)))
           (when (org-element-type-p element 'keyword)
             (forward-line 0)
             ;; Extract arguments from keyword's value.