[FEATURE] Add weights of naflexvit-siglip2

[seefun]

naflexvit_base_patch16_siglip and naflexvit_so400m_patch16_siglip pretrained weights is missing

Is it possible to convert them to the timm vision backbone weight

• https://huggingface.co/google/siglip2-base-patch16-naflex
• https://huggingface.co/google/siglip2-so400m-patch16-naflex

[rwightman]

@seefun it is possible, and I've got the code to load them for working on the OpenCLIP integration (zero-shot eval verified), I can push something up for just the encoder this week.