models : remove redundant ggml_cont calls now supported by all unary kernels (#30198)
* models: remove redundant ggml_cont calls now supported by CUDA unary kernels
* models: restore cont_2d after sigmoid for broadcast mul, clean dflash cont
* Update src/models/qwen3next.cpp
Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@huggingface.co>
* models: restore cont_2d before sigmoid in qwen3next
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Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@huggingface.co>