chore: bump SGLang version to 0.5.6 (#14316)

Co-authored-by: sglang-bot <sglang-bot@users.noreply.github.com>

test/nightly/test_deepseek_v32_nsabackend.py

@@ -197,6 +197,7 @@ class TestDeepseekV32NasBackend_fp8kvcache(CustomTestCase):
         self.assertGreater(metrics["accuracy"], 0.935)
 
 
+@unittest.skip("Temporary skip pure TP test")
 class TestDeepseekV32NasBackend_pure_tp(CustomTestCase):
     """Test DeepSeek V3.2 with pure TP mode (no DP attention)."""