Restore a conditional check I had deleted accidentally

Author: bbatsov

cider.el

@@ -483,9 +483,12 @@ Added to `cider-jack-in-lein-plugins' (which see) when doing
   "Return a normalized list of Leiningen plugins to be injected.
 See `cider-jack-in-lein-plugins' for the format, except that the list
 returned by this function does not include keyword arguments."
-  (let ((plugins (append cider-jack-in-lein-plugins
-                         `(("mx.cider/enrich-classpath" "1.8.0")
-                           ("cider/cider-nrepl" ,cider-injected-middleware-version)))))
+  (let ((plugins (if cider-enrich-classpath
+                     (append cider-jack-in-lein-plugins
+                             `(("cider/cider-nrepl" ,cider-injected-middleware-version)
+                               ("mx.cider/enrich-classpath" "1.8.0")))
+                   (append cider-jack-in-lein-plugins
+                             `(("cider/cider-nrepl" ,cider-injected-middleware-version))))))
     (thread-last plugins
       (seq-filter
        (lambda (spec)