[Perf][Qwen3-TTS] Drop default seed from qwen3_tts.yaml to restore batched MTP sampling (#4970)

Signed-off-by: Yueqian Lin <linyueqian@outlook.com>

vllm_omni/deploy/qwen3_tts.yaml

@@ -58,7 +58,6 @@ stages:
       # it, checkpoints that sample codec EOS on the first frame return empty
       # audio (HTTP 400). See #4962.
       min_tokens: 2
-      seed: 42
       repetition_penalty: 1.05
     subtalker_sampling_params:
       do_sample: true
@@ -89,7 +88,6 @@ stages:
       top_p: 1.0
       top_k: -1
       max_tokens: 65536
-      seed: 42
       repetition_penalty: 1.0
 
 platforms: