feat: add support for together ai

Signed-off-by: Anupam Kumar <kyteinsky@gmail.com>

Author: kyteinsky

lib/Service/OpenAiAPIService.php

@@ -91,10 +91,15 @@ public function getModels(string $userId): array {
 
 		$modelsResponse = $this->request($userId, 'models');
 		$this->logger->debug('Actually getting OpenAI models with a network request');
-		if (!isset($modelsResponse['data'])) {
+		if (isset($modelsResponse['error'])) {
 			$this->logger->warning('Error retrieving models: ' . json_encode($modelsResponse));
 			throw new Exception($this->l10n->t('Unknown models error'), Http::STATUS_INTERNAL_SERVER_ERROR);
 		}
+
+		if (!isset($modelsResponse['data'])) {
+			// also consider responses without 'data' as valid
+			$modelsResponse = ['data' => $modelsResponse];
+		}
 		$cache->set($cacheKey, $modelsResponse, Application::MODELS_CACHE_TTL);
 		$this->modelsMemoryCache = $modelsResponse;
 		return $modelsResponse;