refactor: drop superorder from metas (#44422)

* refactor: create superOrder from superblock

* chore: drop superOrders from meta

* fix: return null for 'certifications'

* fix: only set superOrder if it is needed

* fix(tests): remove filter from order tests

* test: use getSuperOrder, since superOrder has gone

* test: ignore certificates

* fix: getSuperOrder throw for 'certifications'

* test: remove certificate special case

It wasn't necessary, anyway (it had never been working because I put
certificate not certification)

Co-authored-by: Nicholas Carrigan <nhcarrigan@gmail.com>

curriculum/challenges/_meta/json-apis-and-ajax/meta.json

@@ -11,7 +11,6 @@
     }
   ],
   "superBlock": "data-visualization",
-  "superOrder": 3,
   "challengeOrder": [
     [
       "587d7fad367417b2b2512be1",