improve testcase for deposit and deposit with message

[byteZorvin]

1. The edge cases of deposit and deposit_with_messge call a common internal function accept_deposit which can be directly tested instead of making edge cases for both of them.

2. Similarly deposit_reclaim and deposit_with_message_reclaim where testcaes have same edge cases with both the functions. We can create a functions that has the cancels the message, think of way to not replicate the testcases

3. deposit_cancel_request and deposit_with_message_cancel_request can also be improved by calling the start_cancellation in a common function from both of them

• Remove the integration test and instead use mock_state_for_testing() function to test the internal function
• This will improve the overall readability and maintainability of the testcases