Fix OCM validation errors

Signed-off-by: jld3103 <jld3103yt@gmail.com>

Author: provokateurin

lib/public/Federation/Exceptions/BadRequestException.php

@@ -65,7 +65,7 @@ public function getReturnMessage() {
 		];
 
 		foreach ($this->parameterList as $missingParameter) {
-			$result['validationErrors'] = [
+			$result['validationErrors'][] = [
 				'name' => $missingParameter,
 				'message' => 'NOT_FOUND'
 			];