[dreambooth] low precision guard (#1916)
* [dreambooth] low precision guard
* fix
* add docs to cli args
* Update examples/dreambooth/train_dreambooth.py
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>
* style
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>
