misc: encode bytes when producing json output (#36515)

wcs/qommon/misc.py

@@ -487,6 +487,9 @@ class JSONEncoder(json.JSONEncoder):
         if isinstance(obj, decimal.Decimal):
             return str(obj)
 
+        if six.PY3 and isinstance(obj, bytes):
+            return obj.decode('ascii')
+
         if hasattr(obj, 'base_filename'):
             return {
                 'filename': obj.base_filename,