Remove crypto shims (#4292)

* Inline subtlecrypto shim

The presence of this thing just makes code more confusing.

* Remove pre-node-20 webcrypto hack

Until node 20.0, the webcrypto API lived at `crypto.webCrypto`. It's now
available at the same place as in web -- `globalThis.crypto`.

See: https://nodejs.org/docs/latest-v20.x/api/webcrypto.html#web-crypto-api

* oidc auth test: Clean up mocking

THe previous reset code wasn't really resetting the right thing. Let's just
re-init `window.crypto` on each test.

* Remove `crypto` shim

This isn't very useful any more.

src/rust-crypto/rust-crypto.ts

@@ -62,7 +62,6 @@ import { CrossSigningIdentity } from "./CrossSigningIdentity";
 import { secretStorageCanAccessSecrets, secretStorageContainsCrossSigningKeys } from "./secret-storage";
 import { keyFromPassphrase } from "../crypto/key_passphrase";
 import { encodeRecoveryKey } from "../crypto/recoverykey";
-import { crypto } from "../crypto/crypto";
 import { isVerificationEvent, RustVerificationRequest, verificationMethodIdentifierToMethod } from "./verification";
 import { EventType, MsgType } from "../@types/event";
 import { CryptoEvent } from "../crypto";
@@ -891,7 +890,7 @@ export class RustCrypto extends TypedEventEmitter<RustCryptoEvents, RustCryptoEv
         } else {
             // Using the navigator crypto API to generate the private key
             const key = new Uint8Array(32);
-            crypto.getRandomValues(key);
+            globalThis.crypto.getRandomValues(key);
             return {
                 privateKey: key,
                 encodedPrivateKey: encodeRecoveryKey(key),