[docs] Remove pipeline() examples from summarization/translation tasks (#43831)
Remove pipeline()-based inference examples from summarization and
translation task documentation since SummarizationPipeline and
TranslationPipeline were removed in transformers v5.
The manual tokenize/generate/decode workflow remains as the
recommended approach for inference.
Fixes #43827
Co-authored-by: Hari <kp.hari@icloud.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>