fix: detokenization case where first token does not start with a leading space (#1375)

* Fix tokenization edge case where llama output does not start with a space

See this notebook:
https://colab.research.google.com/drive/1Ooz11nFPk19zyJdMDx42CeesU8aWZMdI#scrollTo=oKpHw5PZ30uC

* Update _internals.py

Fixing to compare to b' ' instead of (str)' '

---------

Co-authored-by: Andrei <abetlen@gmail.com>

llama_cpp/_internals.py

@@ -203,7 +203,7 @@ class _LlamaModel:
         # NOTE: Llama1 models automatically added a space at the start of the prompt
         # this line removes a leading space if the first token is a beginning of sentence token
         return (
-            output[1:] if len(tokens) > 0 and tokens[0] == self.token_bos() else output
+            output[1:] if len(tokens) > 0 and tokens[0] == self.token_bos() and output[0:1] == b' ' else output
         )
 
     # Extra