Consolidate error handling by introducing a new AuthResult class and updating display logic in several screens. Also removes passkey prompt in SiwG flow.

Author: cy245

Shrine/app/src/main/java/com/authentication/shrine/model/AuthResult.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.authentication.shrine.model
+
+sealed class AuthResult<out T> {
+    data class Success<out T>(val data: T) : AuthResult<T>()
+    data class Failure(val error: AuthError) : AuthResult<Nothing>()
+}
+
+sealed class AuthError {
+    object NetworkError : AuthError()
+    object UserAlreadyExists : AuthError()
+    object InvalidCredentials : AuthError()
+    data class ServerError(val message: String?) : AuthError()
+    data class Unknown(val message: String?) : AuthError()
+}