[docs] LTX-2.5 Modular Pipeline Docs (#14450)
* LTX-2.5 modular pipeline init docs
* Update LTX-2.5 modular docs now that the modular pipeline automatic downloads the Gemma 4 prompt enhancer and processor
* fix some modular docs typos
* fix more typos
* Update docs/source/en/api/pipelines/ltx2.md
Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>
* Remove unused transformers imports from LTX-2.5 modular examples
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Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>
