Update ErrorFeature

Example/example-app/Package.swift

@@ -59,6 +59,10 @@ let package = Package(
       url: "https://github.com/kishikawakatsumi/KeychainAccess.git",
       .upToNextMajor(from: "4.2.2")
     ),
+    .package(
+      url: "https://github.com/pointfreeco/xctest-dynamic-overlay.git",
+      .upToNextMajor(from: "0.3.3")
+    ),
   ],
   targets: [
     .target(
@@ -106,6 +110,10 @@ let package = Package(
           name: "ElixxirDAppsSDK",
           package: "elixxir-dapps-sdk-swift"
         ),
+        .product(
+          name: "XCTestDynamicOverlay",
+          package: "xctest-dynamic-overlay"
+        ),
       ],
       swiftSettings: swiftSettings
     ),

Example/example-app/Sources/ErrorFeature/ErrorFeature.swift

 import ComposableArchitecture
-import SwiftUI
+import XCTestDynamicOverlay
 
 public struct ErrorState: Equatable {
   public init(error: NSError) {
@@ -17,8 +17,6 @@ public struct ErrorEnvironment {
 
 public let errorReducer = Reducer<ErrorState, ErrorAction, ErrorEnvironment>.empty
 
-#if DEBUG
 extension ErrorEnvironment {
-  public static let failing = ErrorEnvironment()
+  public static let unimplemented = ErrorEnvironment()
 }
-#endif