feat(capabilities): fix object vs array return type for json_encode

Signed-off-by: Florian Wagner <f.wagner81@gmail.com>

Author: multiphlow

lib/Capabilities.php

@@ -153,7 +153,7 @@ public function getDefaultMimetypes(): array {
 			$defaultMimetypes[] = 'application/pdf';
 		}
 
-		return array_unique($defaultMimetypes);
+		return array_values(array_unique($defaultMimetypes));
 	}
 
 	/**

lib/Service/DiscoveryService.php

@@ -156,6 +156,6 @@ public function getSupportedMimeTypes(): array
             $mimeTypes[] = $mimeTypeName;
         }
 
-        return array_unique($mimeTypes);
+        return array_values(array_unique($mimeTypes));
     }
 }