checkpoint model on first step callback (#2906)

* checkpoint model on first step callback

* remove debug

* add test cases; update existing tests not to save on first step

* move test out of solo

* delete

* default to False

* typo

tests/e2e/integrations/test_llm_compressor.py

@@ -81,6 +81,7 @@ class TestLLMCompressorIntegration:
                     },
                     "save_compressed": save_compressed,
                 },
+                "save_first_step": False,
             }
         )