feat(tests): update AiProviderServiceTest with JSON formatted message

- Changed the format of the message content in the AiProviderServiceTest to use JSON instead of a string representation.
- Added assertions to verify the expected message format in the responses.

tests/Feature/Service/AiProviderServiceTest.php

@@ -30,7 +30,7 @@ class AiProviderServiceTest extends TestCase
                 'index' => 0,
                 'message' => [
                     'role' => 'assistant',
-                    'content' => '{\'message\': \'Why don\'t scientists trust atoms? Because they make up everything!\'}',
+                    'content' => "{\n  \"message\": \"Why don't scientists trust atoms? Because they make up everything!\"\n}",
                     'refusal' => null,
                 ],
                 'logprobs' => null,
@@ -85,6 +85,7 @@ public function test_prompt_with_pictures_sends_correct_request()
             $uploadedPicture
         );
 
+        $this->assertEquals(['message' => "Why don't scientists trust at...thing!"], $response);
     }
 
     public function test_prompt_sends_correct_request()
@@ -108,7 +109,7 @@ public function test_prompt_sends_correct_request()
             'Tell me a joke.'
         );
 
-        $this->assertEquals(['response' => 'test-response'], $response);
+        $this->assertEquals(['message' => "Why don't scientists trust at...thing!"], $response);
     }
 
     public function test_prompt_with_pictures_handles_transcoding_failure()