Fix org-in-archived-heading-p

* lisp/org.el (org-in-archived-heading-p): When called on a heading
with a tag containing org-archive-tag string as a substring, that
heading was incorrectly recognised as archived.  Changed matching
against the whole :tag1:tag2:...: string to matching against tag list
as returned by `org-get-tags'.
* testing/lisp/test-org.el (test-org/in-archived-heading-p): Add test
when one of the heading tags contains org-archive-tag as a substring.

lisp/org.el

@@ -20282,10 +20282,9 @@ This function also checks ancestors of the current headline,
 unless optional argument NO-INHERITANCE is non-nil."
   (cond
    ((org-before-first-heading-p) nil)
-   ((let ((tags (nth 5 (org-heading-components))))
+   ((let ((tags (org-get-tags nil 'local)))
       (and tags
-	   (let ((case-fold-search nil))
-	     (string-match-p org-archive-tag tags)))))
+	   (cl-some (apply-partially #'string= org-archive-tag) tags))))
    (no-inheritance nil)
    (t
     (save-excursion (and (org-up-heading-safe) (org-in-archived-heading-p))))))

testing/lisp/test-org.el

@@ -2103,7 +2103,12 @@
   (should-not
    (org-test-with-temp-text "* Headline :ARCHIVE:\n** Level 2\nBody"
      (goto-char (point-max))
-     (org-in-archived-heading-p t))))
+     (org-in-archived-heading-p t)))
+   ;; Archive tag containing ARCHIVE as substring
+   (should-not
+    (org-test-with-temp-text "* Headline :NOARCHIVE:\n** Level 2\nBody"
+     (goto-char (point-max))
+     (org-in-archived-heading-p))))
 
 (ert-deftest test-org/entry-blocked-p ()
   ;; Check other dependencies.