Use new accessors for VerificationRequest (#11092)

* Switch verification request accessors to go via CryptoApi

part of https://github.com/vector-im/crypto-internal/issues/97

* Update references to `requestVerification`

https://github.com/vector-im/crypto-internal/issues/98

src/verification.ts

@@ -120,6 +120,6 @@ export function pendingVerificationRequestForUser(
 ): VerificationRequest | undefined {
     const dmRoom = findDMForUser(matrixClient, user.userId);
     if (dmRoom) {
-        return matrixClient.findVerificationRequestDMInProgress(dmRoom.roomId);
+        return matrixClient.getCrypto()!.findVerificationRequestDMInProgress(dmRoom.roomId);
     }
 }