fix search pagination cursor, use LastModified of last card

Signed-off-by: Julien Veyssier <eneiluj@posteo.net>

lib/Search/DeckProvider.php

@@ -85,7 +85,7 @@ class DeckProvider implements IProvider {
 		return SearchResult::paginated(
 			'Deck',
 			$results,
-			$cardResults[count($results) - 1]->getLastModified()
+			$cardResults[count($cardResults) - 1]->getLastModified()
 		);
 	}