fix: remove `add_generation_prompt` from H1 tokenizers

chat_template.jinja

@@ -13,5 +13,4 @@
     {%- endif %}
 {%- endif %}{% for message in messages %}{%- if message.role != 'system' %}{{'<|im_start|>' + message['role'] + '
 ' + message['content'] + '<|im_end|>' + '
-'}}{%- endif %}{% endfor %}{% if add_generation_prompt %}{{ '<|im_start|>assistant
-' }}{% endif %}
+'}}{%- endif %}{% endfor %}