Add missing permissions middleware hook (#13205)

Adds a missing middleware hook for `wallet_requestPermissions` that we failed to add in #12243. Also adds a runtime check that throws an error if any expected hooks are not provided to `createMethodMiddleware`.

Co-authored-by: Mark Stacey <markjstacey@gmail.com>

app/scripts/lib/rpc-method-middleware/createMethodMiddleware.js

@@ -13,6 +13,12 @@ const handlerMap = allHandlers.reduce((map, handler) => {
   return map;
 }, new Map());
 
+const expectedHookNames = Array.from(
+  new Set(
+    allHandlers.map(({ hookNames }) => Object.keys(hookNames)).flat(),
+  ).values(),
+);
+
 /**
  * Creates a json-rpc-engine middleware of RPC method implementations.
  *
@@ -24,6 +30,16 @@ const handlerMap = allHandlers.reduce((map, handler) => {
  * @returns {(req: Object, res: Object, next: Function, end: Function) => void}
  */
 export default function createMethodMiddleware(hooks) {
+  // Fail immediately if we forgot to provide any expected hooks.
+  const missingHookNames = expectedHookNames.filter(
+    (hookName) => !Object.hasOwnProperty.call(hooks, hookName),
+  );
+  if (missingHookNames.length > 0) {
+    throw new Error(
+      `Missing expected hooks:\n\n${missingHookNames.join('\n')}\n`,
+    );
+  }
+
   return async function methodMiddleware(req, res, next, end) {
     // Reject unsupported methods.
     if (UNSUPPORTED_RPC_METHODS.has(req.method)) {

app/scripts/metamask-controller.js

@@ -2759,6 +2759,10 @@ export default class MetamaskController extends EventEmitter {
           { origin },
           { eth_accounts: {} },
         ),
+        requestPermissionsForOrigin: this.permissionController.requestPermissions.bind(
+          this.permissionController,
+          { origin },
+        ),
 
         // Custom RPC-related
         addCustomRpc: async ({