Refactor: Clean up type ignore placement in update_memory

[pyob-bot]

Summary of Changes

• Moved the # type: ignore comment to the end of the line in the update_memory method within src/pyob/prompts_and_memory.py.
• This improves code readability and adheres to standard Python linting conventions by keeping the ignore directive inline with the statement it affects.

Technical Impact

• No functional changes were made to the logic of update_memory.
• The change is purely cosmetic and improves maintainability by cleaning up the code structure.