Support Bot API 7.8 (July 31, 2024)

[bernard-ng]

• Added the option for bots to set a Main Mini App, which can be previewed and launched directly from a button in the bot's profile or a link.
• Added the method shareToStory to the class WebApp.
• Added the field has_main_web_app to the class User, which is returned in the response to getMe.
• Added the parameter business_connection_id to the methods pinChatMessage and unpinChatMessage, allowing bots to manage pinned messages on behalf of a business account.