Fix: file close even if file was not opened (#1417)

Fixed a bug where in many implementations of load-file functions the file-close was still
executed even if the file-open resulted in an error.

pkg/manager/jsonschema/gallery.go

@@ -29,10 +29,10 @@ type Gallery struct {
 func LoadGalleryFile(filePath string) (*Gallery, error) {
 	var gallery Gallery
 	file, err := os.Open(filePath)
-	defer file.Close()
 	if err != nil {
 		return nil, err
 	}
+	defer file.Close()
 	var json = jsoniter.ConfigCompatibleWithStandardLibrary
 	jsonParser := json.NewDecoder(file)
 	err = jsonParser.Decode(&gallery)