feat: add inertiaProps method for easier prop extraction in tests

This commit introduces a new `inertiaProps` method in the `TestResponseMacros` class.
The method simplifies the process of retrieving specific props from an Inertia.js response
during testing. It uses Laravel's `Arr::get` utility to handle nested properties and
returns a default value if the specified prop is not found.

Example usage:
$response->inertiaProps('user.name');

This enhancement improves test readability and usability for Inertia.js developers.

Author: ashokatheheroo

src/Testing/TestResponseMacros.php

@@ -3,6 +3,7 @@
 namespace Inertia\Testing;
 
 use Closure;
+use Illuminate\Support\Arr;
 
 class TestResponseMacros
 {
@@ -27,4 +28,12 @@ public function inertiaPage()
             return AssertableInertia::fromTestResponse($this)->toArray();
         };
     }
+
+    public function inertiaProps(?string $propName = null): mixed
+    {
+        return Arr::get(
+            $this->inertiaPage()['props'] ?? [],
+            $propName
+        );
+    }
 }