Fulltext support pdf and docx file via datalink

[cpegeric]

What type of PR is this?

• [ ] API-change
• [ ] BUG
• [ ] Improvement
• [ ] Documentation
• [x] Feature
• [ ] Test and CI
• [ ] Code Refactoring

Which issue(s) this PR fixes:

issue #18869

What this PR does / why we need it:

fulltext index support pdf and docx files as content via datalink type