lisp/ox-beamer.el: fix orgframe environment definition

* (org-beamer-template):  pass the frame overlay specification to the
frame in the definition of the orgframe environment.

Bug reported by Pedro Andres Aranda Gutierrez.

Ref: https://list.orgmode.org/orgmode/CF58E7A4-233D-4F9D-BBE2-FC1A67E315BD@gmail.com/T/

lisp/ox-beamer.el

@@ -852,7 +852,7 @@ holding export options."
      ;; Document class and packages.
      (org-latex-make-preamble info)
      ;; Define the alternative frame environment.
-     (format "\\newenvironment<>{%s}[1][]{\\begin{frame}[environment=%1$s,#1]}{\\end{frame}}\n"
+     (format "\\newenvironment<>{%s}[1][]{\\begin{frame}#2[environment=%1$s,#1]}{\\end{frame}}\n"
              org-beamer-frame-environment)
      ;; Insert themes.
      (let ((format-theme