added Self as default associatedtype value for TestDependencyKey.value (#1395)

* added Self as default associatedtype value for TestDependencyKey.value

* Update Tests/ComposableArchitectureTests/DependencyKeyTests.swift

Co-authored-by: Brandon Williams <[email protected]>

Author: pteasima

Sources/Dependencies/DependencyKey.swift

@@ -40,7 +40,7 @@ extension DependencyKey {
 /// See ``DependencyKey`` to define a static, default value for the live application.
 public protocol TestDependencyKey {
   /// The associated type representing the type of the dependency key's value.
-  associatedtype Value
+  associatedtype Value = Self
   // NB: This associated type should be constrained to `Sendable` when this bug is fixed:
   //     https://github.com/apple/swift/issues/60649