cargo_dump.php: remove redundant db query
cargo_dump.php: remove redundant db query

The right panel needs to query the ship cargo anyway (and it does
so through the `SmrShip::getCargo` method), so we use the same
method here to take advantage of the cache.

hemberger/smr,smrealms/smr,hemberger/smr,smrealms/smr,smrealms/smr,hemberger/smr,hemberger/smr