refactor: Remove Epub document loader override (no-changelog) (#7874)

- Remove Epub document loader override, use standard Langchain loader
- Use temporary buffer file for document loader processing and pass just
the path
- Remove replace `@gxl/epub-parser` library with `epub2`

Github issue / Community forum post (link here to close automatically):

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Signed-off-by: Oleg Ivaniv <me@olegivaniv.com>
Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>

packages/@n8n/nodes-langchain/nodes/document_loaders/DocumentDefaultDataLoader/DocumentDefaultDataLoader.node.ts

@@ -15,7 +15,7 @@ import { metadataFilterField } from '../../../utils/sharedFields';
 // here only to track where what dependency is sued
 // import 'd3-dsv'; // for csv
 import 'mammoth'; // for docx
-import '@gxl/epub-parser'; // for epub
+import 'epub2'; // for epub
 import 'pdf-parse'; // for pdf
 import { N8nJsonLoader } from '../../../utils/N8nJsonLoader';