Element-R: Basic implementation of SAS verification (#3490)

* Return uploaded keys from `/keys/query`

* Basic implementation of SAS verification in Rust

* Update the `verifier` *before* emitting `erificationRequestEvent.Change`

* remove dead code

src/client.ts

@@ -2238,6 +2238,8 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
             this.secretStorage,
             this.cryptoCallbacks,
         );
+        rustCrypto.supportedVerificationMethods = this.verificationMethods;
+
         this.cryptoBackend = rustCrypto;
 
         // attach the event listeners needed by RustCrypto