[design] Search bar error states / helper

[aulneau]

The input validates either a tx_id, which would be a hash -> https://github.com/blockstack/explorer/blob/86074e982e00f075cecea175c370834915d8fa7f/src/common/utils.ts#L50 or a contract name -> https://github.com/blockstack/explorer/blob/86074e982e00f075cecea175c370834915d8fa7f/src/common/utils.ts#L55.

We need an error state to display which one is invalid, and some helpful information for using the search. How would a user know to search for a contract name or tx_id?

Also, with the recently viewed component living below the search bar, the typical location of below the input for errors won't work as well.