Fix bugs in LLaVA NeXT model with padding and CPU initialization options

[eagle705]

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What does this PR do ?

This PR addresses bug fixes in the LLaVA NeXT model, specifically adding padding functionality and introducing a use_cpu_init argument to export nemo model to HF format without requiring a GPU or avoiding OOM error

Collection: vlm/llava_next

Changelog

• Added pad_to_multiple_of to support training without packed sequences.
• Introduced use_cpu_init argument to enable HFExporter functionality without requiring a GPU.

Usage

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• [ ] New Feature
• [x] Bugfix
• [ ] Documentation

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@abhinavg4

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Additional Information

• Related to # (issue)