improve: Optimize getRunningBalances computation

[nicholaspai]

Improves relayer and monitor performance by loading more data from arweave optimistically, or in the relayer's case, not at all.

While working on across-protocol/sdk#884, I realized that the only usage of the BundleDataClient' getLatestPoolRebalanceRoot function is the InventoryClient's getLatestRunningBalances function.

getLatestPoolRebalanceRoot is unneccessarily complicated and I actually think we can bypass it entirely in the InventoryClient.

The goal of getLatestRunningBalances is to estimate the latest running balances most accurately. This can be done entirely with reconstructing a bundle:

• get the last validated running balance for a chain and token
• get all deposits for that chain and token sent after the last validated bundle end block corresponding to the running balance we computed in the first step
• approximate all refunds taken on the chain and token since the last validated running balance we computed in the first step