LLM OCP API: Fix type errors

Signed-off-by: Marcel Klehr <mklehr@gmx.net>

lib/public/LanguageModel/AbstractLanguageModelTask.php

@@ -6,6 +6,7 @@ use OC\LanguageModel\Db\Task;
 
 abstract class AbstractLanguageModelTask implements ILanguageModelTask {
 	protected ?int $id;
+	protected ?string $output;
 	protected int $status = ILanguageModelTask::STATUS_UNKNOWN;
 
 	final public function __construct(
@@ -26,6 +27,20 @@ abstract class AbstractLanguageModelTask implements ILanguageModelTask {
 
 	abstract public function getType(): string;
 
+	/**
+	 * @return string|null
+	 */
+	final public function getOutput(): ?string {
+		return $this->output;
+	}
+
+	/**
+	 * @param string|null $output
+	 */
+	final public function setOutput(?string $output): void {
+		$this->output = $output;
+	}
+
 	/**
 	 * @return int
 	 */