Update `eth_getBalance` to pass block timestamp for account queries

[victor-yanev]

Update the eth_getBalance method to use the timestamp of the block when calling getAccountPageLimit if a non-null blockNumberOrTagOrHash is passed. If no block number or tag is provided, the method should pass the timestamp of the already fetched latestBlock instead. This update ensures that account balance queries adhere to the new mirror node REST API changes, which now limit data queries to a 60-day time range.

[victor-yanev]

Closed because no changes are needed for eth_getBalance. Only the transactions list in the response from accounts/{id} endpoint would be empty if the account has no transactions in the past 60 days. Everything else reflects what it should be.

When the blockNumberOrTagOrHash is:

• older than 15 mins: our existing logic doesn't use accounts/{id}, it retrieves the balance through the /balances endpoint which is unaffected by the implicit 60d timestamp limit API changes
• not older than 15 mins: our existing logic already uses the links.next field to recursively fetch all transactions whose timestamp >= block.timestamp.to when calling the accounts/{id} endpoint