fix(OpenAiAPIService): correct text processing time update method

This commit fixes a bug where the method updateExpTextProcessingTime incorrectly called getExpImgProcessingTime. The change ensures that text and image processing times are tracked independently.

Additionally, unit tests have been added to verify the correct functionality of processing time tracking for both text and image generations.

Signed-off-by: Misha M.-Kupriyanov <kupriyanov@strato.de>

Author: printminion-co

lib/Service/OpenAiAPIService.php

@@ -953,7 +953,7 @@ public function getExpTextProcessingTime(): int {
 	 * @return void
 	 */
 	public function updateExpTextProcessingTime(int $runtime): void {
-		$oldTime = floatval($this->getExpImgProcessingTime());
+		$oldTime = floatval($this->getExpTextProcessingTime());
 		$newTime = (1.0 - Application::EXPECTED_RUNTIME_LOWPASS_FACTOR) * $oldTime + Application::EXPECTED_RUNTIME_LOWPASS_FACTOR * floatval($runtime);
 
 		if ($this->isUsingOpenAi()) {