feat: implement batch data fetching and error handling in DataConnector

[MrRoudyk]

Closes #481

Improvements to data fetching:

• apps/dashboard_app/data_connector.py: Modified the fetch_data method to support batch fetching with a new batch_size parameter. This allows for more efficient data retrieval by paginating the results.
• apps/dashboard_app/data_connector.py: Added a new method fetch_protocol_last_block_number to fetch the last block number for a specific protocol, enhancing the flexibility of the data connector.

Enhancements to error handling:

• apps/dashboard_app/helpers/load_data.py: Wrapped the data fetching and processing logic in a try block within the _init_zklend_state method to handle potential exceptions and log errors. This improves the robustness of the data initialization process.

These changes collectively enhance the efficiency, flexibility, and reliability of the data handling processes within the application.

[djeck1432]

Please, add first/last block number method to use instead of while True
so you will go through range of block numbers

[djeck1432]

Okay, now looks better