Revert "checkpoint model on first step callback (#2906)"

This reverts commit 10ba1622f7.

examples/llama-4/do-no-use-fa2/maverick-qlora-fsdp1.yaml

@@ -86,5 +86,3 @@ fsdp_config:
 special_tokens:
   pad_token: <|finetune_right_pad_id|>
   eos_token: <|eot|>
-
-# save_first_step: true  # uncomment this to validate checkpoint saving works with your config

examples/llama-4/do-no-use-fa2/scout-qlora-fsdp1.yaml

@@ -90,5 +90,3 @@ fsdp_config:
 special_tokens:
   pad_token: <|finetune_right_pad_id|>
   eos_token: <|eot|>
-
-# save_first_step: true  # uncomment this to validate checkpoint saving works with your config

examples/llama-4/do-no-use-fa2/scout-qlora-single-h100.yaml

@@ -83,5 +83,3 @@ weight_decay: 0.0
 special_tokens:
   pad_token: <|finetune_right_pad_id|>
   eos_token: <|eot|>
-
-# save_first_step: true  # uncomment this to validate checkpoint saving works with your config

examples/llama-4/do-no-use-fa2/scout-vision-qlora-fsdp.yaml

@@ -86,5 +86,3 @@ fsdp_config:
 special_tokens:
   pad_token: <|finetune_right_pad_id|>
   eos_token: <|eot|>
-
-# save_first_step: true  # uncomment this to validate checkpoint saving works with your config

examples/llama-4/scout-qlora-flexattn-fsdp2.yaml

@@ -84,5 +84,3 @@ fsdp_config:
 special_tokens:
   pad_token: <|finetune_right_pad_id|>
   eos_token: <|eot|>
-
-# save_first_step: true  # uncomment this to validate checkpoint saving works with your config

examples/llama-4/scout-qlora-single-h100-flex.yaml

@@ -82,5 +82,3 @@ weight_decay: 0.0
 special_tokens:
   pad_token: <|finetune_right_pad_id|>
   eos_token: <|eot|>
-
-# save_first_step: true  # uncomment this to validate checkpoint saving works with your config

examples/llama-4/scout-vision-qlora-fsdp2-flex.yaml

@@ -87,5 +87,3 @@ fsdp_config:
 special_tokens:
   pad_token: <|finetune_right_pad_id|>
   eos_token: <|eot|>
-
-# save_first_step: true  # uncomment this to validate checkpoint saving works with your config