added doc for Kandinsky3.0 (#5937)
* added en doc for Kandinsky3.0
* required changes
* Update docs/source/en/api/pipelines/kandinsky3.md
* Update docs/source/en/api/pipelines/kandinsky3.md
* Update docs/source/en/api/pipelines/kandinsky3.md
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Co-authored-by: YiYi Xu <yixu310@gmail.com>
Co-authored-by: Patrick von Platen <patrick.v.platen@gmail.com>
