fix(files): Fix non-string values for activity rich object strings

Signed-off-by: provokateurin <[email protected]>

Author: provokateurin

apps/files/lib/Activity/Provider.php

@@ -323,7 +323,7 @@ protected function getFile($parameter, ?IEvent $event = null): array {
 		} elseif ($event !== null) {
 			// Legacy from before ownCloud 8.2
 			$path = $parameter;
-			$id = $event->getObjectId();
+			$id = (string)$event->getObjectId();
 		} else {
 			throw new UnknownActivityException('Could not generate file parameter');
 		}
@@ -341,7 +341,7 @@ protected function getFile($parameter, ?IEvent $event = null): array {
 
 				return [
 					'type' => 'file',
-					'id' => $encryptionContainer->getId(),
+					'id' => (string)$encryptionContainer->getId(),
 					'name' => $encryptionContainer->getName(),
 					'path' => $path,
 					'link' => $this->url->linkToRouteAbsolute('files.viewcontroller.showFile', ['fileid' => $encryptionContainer->getId()]),