Revert "Remove redundant error class"

This reverts commit 85cc582.

Author: abnegate

src/SDK/Language/Kotlin.php

@@ -288,6 +288,12 @@ public function getFiles()
                 'template'      => '/kotlin/src/main/java/io/appwrite/extensions/JsonExtensions.kt.twig',
                 'minify'        => false,
             ],
+            [
+                'scope'         => 'default',
+                'destination'   => '/src/main/java/{{ sdk.namespace | caseSlash }}/models/Error.kt',
+                'template'      => '/kotlin/src/main/java/io/appwrite/models/Error.kt.twig',
+                'minify'        => false,
+            ],
             [
                 'scope'         => 'default',
                 'destination'   => '/build.gradle',

templates/kotlin/src/main/java/io/appwrite/models/Error.kt.twig

@@ -0,0 +1,6 @@
+package {{ sdk.namespace | caseDot }}.models
+
+data class Error(
+    val message: String,
+    val code: Int
+)