Package: Validate challenges on test (#17216)

This PR allows us to validate the schema during test.

It also removes some cruft from the seed files and ensures only the required data is packaged and consumable, reducing the package weight somewhat.

schema/challengeSchema.js

@@ -4,9 +4,6 @@ Joi.objectId = require('joi-objectid')(Joi);
 const schema = Joi.object().keys({
   block: Joi.string(),
   blockId: Joi.objectId(),
-  challengeSeed: Joi.array().items(
-    Joi.string().allow('')
-  ),
   challengeType: Joi.number().min(0).max(9).required(),
   checksum: Joi.number(),
   dashedName: Joi.string(),
@@ -20,15 +17,21 @@ const schema = Joi.object().keys({
       key: Joi.string(),
       ext: Joi.string(),
       name: Joi.string(),
-      head: Joi.string().allow(''),
-      tail: Joi.string().allow(''),
-      contents: Joi.string().allow('')
+      head: [
+        Joi.array().items(Joi.string().allow('')),
+        Joi.string().allow('')
+      ],
+      tail: [
+        Joi.array().items(Joi.string().allow('')),
+        Joi.string().allow('')
+      ],
+      contents: [
+        Joi.array().items(Joi.string().allow('')),
+        Joi.string().allow('')
+      ]
     })
   ),
   guideUrl: Joi.string().uri({ scheme: 'https' }),
-  head: Joi.array().items(
-    Joi.string().allow('')
-  ),
   helpRoom: Joi.string(),
   id: Joi.objectId().required(),
   isBeta: Joi.bool(),
@@ -52,13 +55,16 @@ const schema = Joi.object().keys({
   superBlock: Joi.string(),
   superOrder: Joi.number(),
   suborder: Joi.number(),
-  tail: Joi.array().items(
-    Joi.string().allow('')
-  ),
   tests: Joi.array().items(
+    // public challenges
     Joi.object().keys({
       text: Joi.string().required(),
       testString: Joi.string().allow('').required()
+    }),
+    // our tests used in certification verification
+    Joi.object().keys({
+      id: Joi.string().required(),
+      title: Joi.string().required()
     })
   ),
   template: Joi.string(),