Make more of the codebase conform to strict types (#10857)

src/IdentityAuthClient.tsx

@@ -16,7 +16,7 @@ limitations under the License.
 
 import React from "react";
 import { SERVICE_TYPES } from "matrix-js-sdk/src/service-types";
-import { createClient, MatrixClient } from "matrix-js-sdk/src/matrix";
+import { createClient, MatrixClient, MatrixError } from "matrix-js-sdk/src/matrix";
 import { logger } from "matrix-js-sdk/src/logger";
 
 import { MatrixClientPeg } from "./MatrixClientPeg";
@@ -123,7 +123,7 @@ export default class IdentityAuthClient {
         try {
             await this.matrixClient.getIdentityAccount(token);
         } catch (e) {
-            if (e.errcode === "M_TERMS_NOT_SIGNED") {
+            if (e instanceof MatrixError && e.errcode === "M_TERMS_NOT_SIGNED") {
                 logger.log("Identity server requires new terms to be agreed to");
                 await startTermsFlow([new Service(SERVICE_TYPES.IS, identityServerUrl, token)]);
                 return;