fix: tracing_subscriber problem in kona-derive tests

[steph-rs]

This PR provides fix for tracing_subscriber initialization at kona-derive tests.
command to reproduce:

cd crates/derive; cargo test 

the result:

---- batch::span_batch::batch::tests::test_check_batch_exceeds_sequencer_time_drift stdout ----
thread 'batch::span_batch::batch::tests::test_check_batch_exceeds_sequencer_time_drift' panicked at .cargo/registry/src/index.crates.io-6f17d22bba15001f/tracing-subscriber-0.3.18/src/util.rs:91:14:
failed to set global default subscriber: SetGlobalDefaultError("a global default trace dispatcher has already been set")
...
  
test result: FAILED. 216 passed; 34 failed; 1 ignored; 0 measured; 0 filtered out; finished in 0.02s

with this fix:

test result: ok. 250 passed; 0 failed; 1 ignored; 0 measured; 0 filtered out; finished in 0.05s

[refcell]

Very nice catch!