Fix auto tokenizer import reference format in auto map as list for slow and fast.

config.json

@@ -12,7 +12,10 @@
   "auto_map": {
     "AutoConfig": "configuration_hyena.StripedHyenaConfig",
     "AutoModelForCausalLM": "modeling_hyena.StripedHyenaModelForCausalLM",
-    "AutoTokenizer": "tokenizer.ByteTokenizer"
+    "AutoTokenizer": [
+      "tokenizer.ByteTokenizer",
+      null
+    ]
   },
   "column_split": false,
   "column_split_hyena": true,

tokenizer_config.json

@@ -1,7 +1,10 @@
 {
   "added_tokens_decoder": {},
   "auto_map": {
-    "AutoTokenizer": "tokenizer.ByteTokenizer"
+    "AutoTokenizer": [
+      "tokenizer.ByteTokenizer",
+      null
+    ]
   },
   "byte_level": true,
   "clean_up_tokenization_spaces": true,