[Bugfix][Cosmos3] Avoid logging prompts at INFO level (#6913)

Signed-off-by: Rahul Steiger <rsteiger@nvl72d233-T16.cm.cluster>
Co-authored-by: Rahul Steiger <rsteiger@nvl72d233-T16.cm.cluster>

vllm_omni/diffusion/models/cosmos3/pipeline_cosmos3.py

@@ -2223,7 +2223,7 @@ class Cosmos3OmniDiffusersPipeline(
         if prompt_suffix:
             prompt = f"{prompt.rstrip()} {prompt_suffix.lstrip()}".strip()
         if _is_rank_zero():
-            logger.info("Final prompt: '%s'", prompt)
+            logger.debug("Final prompt: '%s'", prompt)
 
         if negative_metadata_mode == "none":
             negative_dur_tmpl = None