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/useInteractiveLogin.ts

@@ -40,7 +40,7 @@ export function useInteractiveLogin(
 
       const interactiveAuth = new InteractiveAuth({
         matrixClient: authClient,
-        doRequest: (): Promise<LoginResponse> =>
+        doRequest: async (): Promise<LoginResponse> =>
           authClient.login("m.login.password", {
             identifier: {
               type: "m.id.user",
@@ -49,9 +49,8 @@ export function useInteractiveLogin(
             password,
           }),
         stateUpdated: (): void => {},
-        requestEmailToken: (): Promise<{ sid: string }> => {
-          return Promise.resolve({ sid: "" });
-        },
+        requestEmailToken: async (): Promise<{ sid: string }> =>
+          Promise.resolve({ sid: "" }),
       });
 
       // XXX: This claims to return an IAuthData which contains none of these