chore: generate mfa secret in backend (#2930) [skip e2e]

* chore: get mfa secret from backend

* chore: remove unused code

packages/snjs/lib/Application/Dependencies/Dependencies.ts

@@ -1229,7 +1229,6 @@ export class Dependencies {
     this.factory.set(TYPES.MfaService, () => {
       return new MfaService(
         this.get<SettingsService>(TYPES.SettingsService),
-        this.get<PureCryptoInterface>(TYPES.Crypto),
         this.get<FeaturesService>(TYPES.FeaturesService),
         this.get<ProtectionsClientInterface>(TYPES.ProtectionService),
         this.get<EncryptionService>(TYPES.EncryptionService),