ComfyUI removed the `flipped_img_txt` attribute from `DoubleStreamBlock`
in a recent refactor (commit e1add563f, "Use torch RMSNorm for flux
models and refactor hunyuan video code"). This causes an AttributeError
when IPAdapter Flux nodes are executed.
Use `getattr` with a default of `False` (matching the original default)
to maintain compatibility with both old and new ComfyUI versions.