Correct long-form generation config parameters 'max_initial_timestamp_index' and 'prev_sot_token_id'.

generation_config.json

@@ -123,10 +123,11 @@
     "<|zh|>": 50260
   },
   "language": "<|en|>",
-  "max_initial_timestamp_index": 1,
+  "max_initial_timestamp_index": 50,
   "max_length": 448,
   "no_timestamps_token_id": 50363,
   "pad_token_id": 50257,
+  "prev_sot_token_id": 50361,
   "return_timestamps": false,
   "suppress_tokens": [
     1,