fix: remove thinkingConfig entirely — field does not exist in Gemini API

The API returned: Unknown name "thinkingConfig": Cannot find field.
gemini-2.5-flash works with a plain generateContent request, no special config needed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/Http/Livewire/Chat/ShowConfiguracionChat.php

@@ -112,10 +112,6 @@ class ShowConfiguracionChat extends Component
                     'contents'         => [['parts' => [['text' => 'Responde solo "ok"']]]],
                     'generationConfig' => ['maxOutputTokens' => 5, 'temperature' => 0],
                 ];
-                if (preg_match('/gemini-(2\.5|3[\.\d]*)/', $model)) {
-                    $body['thinkingConfig'] = ['thinkingBudget' => 0];
-                }
-
                 $response = Http::timeout(15)
                     ->withHeaders(['Content-Type' => 'application/json'])
                     ->post("{$url}?key={$key}", $body);