[gimp] Fix missing return in file-jpegxl.c

[Jehan <jehanp src gnome org>]

commit ea6bcef36066eff77b565b25c05c7b1af93a5886
Author: Daniel Novomesky <dnovomesky gmail com>
Date:   Fri Oct 1 12:04:52 2021 +0200

    Fix missing return in file-jpegxl.c

 plug-ins/common/file-jpegxl.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/plug-ins/common/file-jpegxl.c b/plug-ins/common/file-jpegxl.c
index 0859af7c02..bb8568725a 100644
--- a/plug-ins/common/file-jpegxl.c
+++ b/plug-ins/common/file-jpegxl.c
@@ -886,6 +886,7 @@ save_image (GFile                *file,
           JxlEncoderDestroy (encoder);
           g_free (picture_buffer);
           g_free (filename);
+          return FALSE;
         }
     }
   else