Unable to increase context length in SM serverless customizations

**Describe the feature you'd like**
Currently customers cannot use GRPO for Qwen model customization for models using long context (more than 2048 tokens)

**How would this feature be used? Please describe.**
Should work similar to JumpStart training implementation:
estimator = JumpStartEstimator(
model_id="meta-textgeneration-llama-2-7b",
hyperparameters={
"max_input_length": "4096", # Update context length here
"max_total_tokens": "4096"
}
)

**Describe alternatives you've considered**
Using SM training jobs for GRPO training with recipes.

**Additional context**
Customer: Intuit (a high-priority issue blocking usage of SM serverless customization service).

从 serverless customization 路径开始，并将其配置与 issue 中的 JumpStartEstimator 示例进行比较。跟踪 GRPO customization 如何处理 Qwen 模型以及 max_input_length 和 max_total_tokens 超参数。完成的标准是客户可以在 SM serverless customization 中使用这些设置来支持超过 2048 tokens 的上下文长度。

由索引模型根据 Issue 内容生成。