Improve terms handling for 3PID state gathering

This changes the 3PID state gathering (used in Settings) to ignore terms errors
(no modals will be shown) on the assumption that other UX handles this case.

src/IdentityAuthClient.js

@@ -65,7 +65,7 @@ export default class IdentityAuthClient {
     }
 
     // Returns a promise that resolves to the access_token string from the IS
-    async getAccessToken(check=true) {
+    async getAccessToken({ check = true } = {}) {
         if (!this.authEnabled) {
             // The current IS doesn't support authentication
             return null;