Switch to secure random strings (#29013)

* Switch to secure random strings

Because the js-sdk methods are changing and there's no reason for these
not to use the secure versions. The dedicated upper/lower functions were
*only* used in this one case, so this should do the exact same thing with
the one exported function.

Requires https://github.com/matrix-org/matrix-js-sdk/pull/4621 (merge both together)

* Change remaining instances of randomString

which I somehow entirely missed the first time.

* Fix import order

src/vector/platform/ElectronPlatform.tsx

@@ -12,7 +12,7 @@ Please see LICENSE files in the repository root for full details.
 
 import { MatrixClient, Room, MatrixEvent, OidcRegistrationClientMetadata } from "matrix-js-sdk/src/matrix";
 import React from "react";
-import { randomString } from "matrix-js-sdk/src/randomstring";
+import { secureRandomString } from "matrix-js-sdk/src/randomstring";
 import { logger } from "matrix-js-sdk/src/logger";
 
 import BasePlatform, { UpdateCheckStatus, UpdateStatus } from "../../BasePlatform";
@@ -93,7 +93,7 @@ export default class ElectronPlatform extends BasePlatform {
     private readonly ipc = new IPCManager("ipcCall", "ipcReply");
     private readonly eventIndexManager: BaseEventIndexManager = new SeshatIndexManager();
     // this is the opaque token we pass to the HS which when we get it in our callback we can resolve to a profile
-    private readonly ssoID: string = randomString(32);
+    private readonly ssoID: string = secureRandomString(32);
 
     public constructor() {
         super();