Enable lint rules for Promise handling to discourage misuse of them. (#2607)

* Enable lint rules for Promise handling to discourage misuse of them.
Squashed all of Hugh's commits into one.

---------

Co-authored-by: Hugh Nimmo-Smith <hughns@element.io>

src/auth/useInteractiveRegistration.ts

@@ -12,6 +12,7 @@ import {
   MatrixClient,
   RegisterResponse,
 } from "matrix-js-sdk/src/matrix";
+import { logger } from "matrix-js-sdk/src/logger";
 
 import { initClient } from "../utils/matrix";
 import { Session } from "../ClientContext";
@@ -66,7 +67,7 @@ export const useInteractiveRegistration = (
     ): Promise<[MatrixClient, Session]> => {
       const interactiveAuth = new InteractiveAuth({
         matrixClient: authClient.current!,
-        doRequest: (auth): Promise<RegisterResponse> =>
+        doRequest: async (auth): Promise<RegisterResponse> =>
           authClient.current!.registerRequest({
             username,
             password,
@@ -78,19 +79,26 @@ export const useInteractiveRegistration = (
           }
 
           if (nextStage === "m.login.terms") {
-            interactiveAuth.submitAuthDict({
-              type: "m.login.terms",
-            });
+            interactiveAuth
+              .submitAuthDict({
+                type: "m.login.terms",
+              })
+              .catch((e) => {
+                logger.error(e);
+              });
           } else if (nextStage === "m.login.recaptcha") {
-            interactiveAuth.submitAuthDict({
-              type: "m.login.recaptcha",
-              response: recaptchaResponse,
-            });
+            interactiveAuth
+              .submitAuthDict({
+                type: "m.login.recaptcha",
+                response: recaptchaResponse,
+              })
+              .catch((e) => {
+                logger.error(e);
+              });
           }
         },
-        requestEmailToken: (): Promise<{ sid: string }> => {
-          return Promise.resolve({ sid: "dummy" });
-        },
+        requestEmailToken: async (): Promise<{ sid: string }> =>
+          Promise.resolve({ sid: "dummy" }),
       });
 
       // XXX: This claims to return an IAuthData which contains none of these