add models for T2I-Adapter-XL (#4696)
* T2I-Adapter-XL
* update
* update
* add pipeline
* modify pipeline
* modify pipeline
* modify pipeline
* modify pipeline
* modify pipeline
* modify modeling_text_unet
* fix styling.
* fix: copies.
* adapter settings
* new test case
* new test case
* debugging
* debugging
* debugging
* debugging
* debugging
* debugging
* debugging
* debugging
* revert prints.
* new test case
* remove print
* org test case
* add test_pipeline
* styling.
* fix copies.
* modify test parameter
* style.
* add adapter-xl doc
* double quotes in docs
* Fix potential type mismatch
* style.
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Co-authored-by: sayakpaul <spsayakpaul@gmail.com>
