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

generation_config.json

@@ -35,10 +35,11 @@
     ]
   ],
   "is_multilingual": false,
-  "max_initial_timestamp_index": 1,
+  "max_initial_timestamp_index": 50,
   "max_length": 448,
   "no_timestamps_token_id": 50362,
   "pad_token_id": 50256,
+  "prev_sot_token_id": 50360,
   "return_timestamps": false,
   "suppress_tokens": [
     1,