cmd/faucet: fix nonce-gap problem (#22145)

* cmd/faucet: avoid encoding for each client

* cmd/faucet: fix flaw in clearing of txs, avoid sending more than necessary

* cmd/faucet: fix flaw in tx cropping

* cmd/faucet: revert change to not always send tx info

* cmd/faucet: review fixes

* cmd/faucet: revert #22018, fix order in UI

* cmd/faucet: fix lock error

* cmd/faucet: revert json changes

* squashme