- Replaced `getUpdate()->getMessage()->text` with `getUpdate()->getText()` to simplify text retrieval.
- Improved `relevantMessageSubString` method to better handle different message formats and avoid potential errors.

- Updated `handler` method to handle `callback_query` updates.
- Implemented command parsing for callback queries with format `/callback:::\w*`.
- Maintained existing command parsing and execution for regular messages.
- Ensured backward compatibility with previous command handling logic.

- Implemented `getText` method to retrieve text from various update types:
  - Returns message text for 'message', 'edited_message', 'channel_post', and 'edited_channel_post' types.
  - Returns formatted callback query data for 'callback_query' type.
  - Returns empty string for other types.
- Updated docblocks to reflect the new method.
- Maintained backward compatibility with deprecated methods.

- Implemented `getText` method to retrieve text from various update types:
  - Returns message text for 'message', 'edited_message', 'channel_post', and 'edited_channel_post' types.
  - Returns formatted callback query data for 'callback_query' type.
  - Returns empty string for other types.
- Updated docblocks to reflect the new method.
- Maintained backward compatibility with deprecated methods.