error handling: empty subgraph data

[denverbaumgartner]

currently, we expect that the result of our queries are not empty, and then proceed to attempting to transform the data. this causes problems when the dataframe actually is empty, and we should handle scenarios like this. an example where this can occur is rubi.data.market_aid_optimism_processing.aid_fill_tracking(aid = aid, asset = asset, quote = quote)