Use async/await for getRestrictedMethods (#9099)

app/scripts/controllers/permissions/restrictedMethods.js

@@ -1,12 +1,11 @@
 export default function getRestrictedMethods ({ getIdentities, getKeyringAccounts }) {
   return {
     'eth_accounts': {
-      method: (_, res, __, end) => {
-        getKeyringAccounts()
-          .then((accounts) => {
+      method: async (_, res, __, end) => {
+        try {
+          const accounts = await getKeyringAccounts()
           const identities = getIdentities()
-            res.result = accounts
-              .sort((firstAddress, secondAddress) => {
+          res.result = accounts.sort((firstAddress, secondAddress) => {
             if (!identities[firstAddress]) {
               throw new Error(`Missing identity for address ${firstAddress}`)
             } else if (!identities[secondAddress]) {
@@ -22,13 +21,10 @@ export default function getRestrictedMethods ({ getIdentities, getKeyringAccount
             return identities[secondAddress].lastSelected - identities[firstAddress].lastSelected
           })
           end()
-          })
-          .catch(
-            (err) => {
+        } catch (err) {
           res.error = err
           end(err)
-            },
-          )
+        }
       },
     },
   }