fix(api): correct misleading error message on empty keyValuePairs

updateQuestion() rejected an empty keyValuePairs array with the message
"This form is archived and can not be modified". That message is unrelated
to the actual cause and sends callers looking in the wrong place.

The sibling methods updateForm() and updateOption() already report this
case accurately, and updateQuestion()'s own @throws annotation documents
it as "Empty keyValuePairs, will not update" too, so the string looks like
a copy-paste leftover from the archived-form check further up.

Only the message is changed. The exception type stays OCSBadRequestException
so the HTTP status code is unaffected.

Signed-off-by: Josef Behr <code@josef-behr.de>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: josefbehr

lib/Controller/ApiController.php

@@ -675,7 +675,7 @@ public function updateQuestion(int $formId, int $questionId, array $keyValuePair
 		// Don't allow empty array
 		if (count($keyValuePairs) === 0) {
 			$this->logger->info('Empty keyValuePairs, will not update.');
-			throw new OCSBadRequestException('This form is archived and can not be modified');
+			throw new OCSBadRequestException('Empty keyValuePairs, will not update.');
 		}
 
 		//Don't allow to change id or formId