Fix incorrect function call in test_qwen3_grpo.py (#3212)

* Update test_qwen3_grpo.py to correct function call

This test file uses the incorrect name for the function, which is gradient_checkpointing_disable(), not disable_gradient_checkpointing(). 

I copied the line from test_llama32_sft.py - I'm not sure if this actually is required, just wanted it consistent for when other people like me test this and have no clue what they're doing when it throws an exception.

* Update blackwell/test_qwen3_grpo.py

Co-authored-by: Daniel Han <[email protected]>

---------

Co-authored-by: Daniel Han <[email protected]>

Author: stevenxdavis

blackwell/test_qwen3_grpo.py

@@ -415,7 +415,8 @@ def check_numbers(prompts, completions, answer, **kwargs):
     top_k=50,
     max_tokens=1024,
 )
-model.disable_gradient_checkpointing()
+
+
 output = (
     model.fast_generate(
         [text],