[From Single File] support `from_single_file` method for `WanAnimateTransformer3DModel` (#12691)
* Add `WanAnimateTransformer3DModel` to `SINGLE_FILE_LOADABLE_CLASSES`
* Fixed dtype mismatch when loading a single file
* Fixed a bug that results in white noise for generation
* Update dtype check for time embedder - caused white noise output
* Improve code readability
* Optimize dtype handling
Removed unnecessary dtype conversions for timestep and weight.
* Apply style fixes
* Refactor time embedding dtype handling
Adjust time embedding type conversion for compatibility.
* Apply style fixes
* Modify comment for WanTimeTextImageEmbedding class
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Co-authored-by: Sam Edwards <sam.edwards1976@gmail.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>