[Examples] Add streaming support to the ControlNet training example in JAX (#2859)
* improve stable unclip doc.
* feat: add streaming support to controlnet flax training script.
* fix: CLI arg.
* fix: torch dataloader shuffle setting.
* fix: dataset length.
* fix: wandb config.
* fix: steps_per_epoch in the training loop.
* add: entry about streaming in the readme
* get column names from iterable dataset + fix final logging
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Co-authored-by: yiyixuxu <yixu310@gmail.com>