[bug] get_funded_wallet() does not return balance

[rajarshimaitra]

Describe the bug
After recent changes in balance calculation, the get_funded_wallet test function will not show any balance because we are not setting the sync_time in the populate_test_db macro..

Our existing tests are not failing, because even if the balance is shown zero, it will still be able to produce transactions. But its causing test failure in downstream bdk-reserves crate where the balances are required to assert scenarios.

To Reproduce

let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
assert_eq!(wallet.get_balance().unwrap().confirmed, 0);

Expected behavior

let (wallet, _, _) = get_funded_wallet(get_test_wpkh());
assert_eq!(wallet.get_balance().unwrap().confirmed, 50000);