ol.el: Skip #CUSTOM_ID when <<target>> link is stored

* list/ol.el (org-store-link): Suppress storing of
"file:file.org::#custom_id" link when point is <<target>>.

CUSTOM_ID link is stored as additional option, so new chunk of code
introduced by b4b35fc92 is not necessary. It prevented adding of
"file:file.org::*Heading" link and caused duplication of
"file:file.org::#custom_id" link.

Reported-by: Fr Ml <fr_ml@t-online.de>
Link: https://orgmode.org/list/aadb23f3-c0fe-19aa-be79-50e51d16c41a@t-online.de/

lisp/ol.el

@@ -1668,7 +1668,9 @@ non-nil."
 			 (abbreviate-file-name
 			  (buffer-file-name (buffer-base-buffer)))
 			 "::" (match-string 1))
-		 link cpltxt))
+		 link cpltxt
+                 ;; Do not append #CUSTOM_ID link below.
+                 custom-id nil))
 	  ((and (featurep 'org-id)
 		(or (eq org-id-link-to-org-use-id t)
 		    (and interactive?