Make delegate optional

Author: kristohear

firebase-auth/src/iosMain/kotlin/dev/gitlive/firebase/auth/credentials.kt

@@ -77,20 +77,14 @@ actual class PhoneAuthProvider(val ios: FIRPhoneAuthProvider) {
     actual fun credential(verificationId: String, smsCode: String): PhoneAuthCredential = PhoneAuthCredential(ios.credentialWithVerificationID(verificationId, smsCode))
 
     actual suspend fun verifyPhoneNumber(phoneNumber: String, verificationProvider: PhoneVerificationProvider): AuthCredential {
-        val verificationId: String = ios.awaitResult {
-            if (verificationProvider.delegate != null) {
-                ios.verifyPhoneNumber(phoneNumber, verificationProvider.delegate as? FIRAuthUIDelegateProtocol, it)
-            } else {
-                ios.verifyPhoneNumber(phoneNumber, null, it)
-            }
-        }
+        val verificationId: String = ios.awaitResult { ios.verifyPhoneNumber(phoneNumber, verificationProvider.delegate, it) }
         val verificationCode = verificationProvider.getVerificationCode()
         return credential(verificationId, verificationCode)
     }
 }
 
 actual interface PhoneVerificationProvider {
-    val delegate: Any?
+    val delegate: FIRAuthUIDelegateProtocol?
     suspend fun getVerificationCode(): String
 }