fix(translation): replace static error message

as suggested by @kesselb in nextcloud/server#25490

Signed-off-by: Samuel <faust64@gmail.com>

lib/private/Share20/Manager.php

@@ -542,7 +542,8 @@ class Manager implements IManager {
 					$this->groupManager->getUserGroupIds($sharedWith)
 			);
 			if (empty($groups)) {
-				throw new \Exception('Sharing is only allowed with group members');
+				$message_t = $this->l->t('Sharing is only allowed with group members');
+				throw new GenericShareException($message_t, $message_t, 404);
 			}
 		}