fix #I6YOA1 [app_chatgpt] 发送prompt长度的限制，在robot增加 max_send_char参数

app_chatgpt/views/ai_robot_views.xml

@@ -12,6 +12,7 @@
                 <field name="openapi_api_key" password="True"/>
                 <field name="max_tokens" optional="show"/>
                 <field name="temperature"/>
+                <field name="max_send_char"/>
             </tree>
         </field>
     </record>
@@ -40,6 +41,7 @@
                             <field name="frequency_penalty"/>
                             <field name="presence_penalty"/>
                             <field name="sys_content" placeholder="Role-playing and scene setting.Give the model instructions about how it should behave and any context it should reference when generating a response."/>
+                            <field name="max_send_char"/>
                         </group>
                         <group>
                             <field name="ai_model"/>