fix: require_latest_height check should skip for requests with height 0

[james-chf]

Ported from fbfc105 in eth-bridge-integration

This was necessary to fix to get a test in eth-bridge-integration to pass (test_bridge_pool_updates)

--- STDOUT:                             namada ledger::queries::shell::test::test_bridge_pool_updates ---

running 1 test
test ledger::queries::shell::test::test_bridge_pool_updates ... FAILED

failures:

failures:
    ledger::queries::shell::test::test_bridge_pool_updates

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 207 filtered out; finished in 0.01s


--- STDERR:                             namada ledger::queries::shell::test::test_bridge_pool_updates ---
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Custom { kind: Other, error: "This query doesn't support arbitrary block heights, only the latest committed block height ('0' can be used as a special value that means the latest block height)" }', shared/src/ledger/queries/shell.rs:634:14
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace