pcli: print height of detected transactions

[hdevalence]

This is useful for working with the DEX, where most of the queries are height-based.
Example output:

     Running `target/release/pcli -n 'http://testnet-preview.penumbra.zone:8080' tx lp order buy '20penumbra@0.9gn' --spread 50`
Scanning blocks from last sync height 522 to latest height 522
[0s] ██████████████████████████████████████████████████       0/0       0/s ETA: 0s
building transaction...
finished proving in 0.874 seconds [4 actions, 3 proofs, 2542 bytes]
broadcasting transaction and awaiting confirmation...
transaction confirmed and detected: 278a6b0a6e7781097551dff250094c0494c32569470bf4f6411c832865d3b68c @ 523

[plaidfinch]

Perhaps should we say @ block 523 to make it self evident what the number means?

[hdevalence]

Any ideas why the smoke test is failing here? I can't tell from the error message.