Fix：Added support for preview of txt, md, excel, csv, ppt, image, doc and other files (#8712)

### What problem does this PR solve?

Added support for preview of txt, md, excel, csv, ppt, image, doc and
other files [#3221](https://github.com/infiniflow/ragflow/issues/3221)

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/package.json

@@ -81,6 +81,7 @@
     "mammoth": "^1.7.2",
     "next-themes": "^0.4.6",
     "openai-speech-stream-player": "^1.0.8",
+    "pptx-preview": "^1.0.5",
     "rc-tween-one": "^3.0.6",
     "react-copy-to-clipboard": "^5.1.0",
     "react-dropzone": "^14.3.5",