When the gas API is down, the logic we use will no longer compute all of
the data that the gas API returns in order to reduce the burden on
Infura. Specifically, only estimated fees for different priority levels,
as well as the latest base fee, will be available; all other data
points, such as the latest and historical priority fee range and network
stability, will be missing. This commit updates the frontend logic to
account for this lack of data by merely hiding the relevant pieces of
the UI that would otherwise be shown.