fixup! feat: use new epoch observer API from CoreCrypto

Author: typfel

wire-ios-data-model/Source/MLS/MLSService.swift

@@ -2186,10 +2186,9 @@ public final class MLSService: MLSServiceInterface {
 
     public func startObservingEpochs() {
         Task {
-            // TODO: [WPB-16966] registerEpochObserver is not exposed on CoreCryptoProtocol
             do {
                 try await coreCrypto.configure { coreCrypto in
-                    try await (coreCrypto as? CoreCrypto)?.registerEpochObserver(self)
+                    try await coreCrypto.registerEpochObserver(self)
                 }
             } catch {
                 logger.error("failed to start epoch observer: \(String(describing: error))")