[Bug] pdfFooterTemplate error

**Describe the bug**
I Add to my docfx.json this settings

```
"globalMetadata": {
"_appTitle": "Réseau ",
"_enableSearch": "true",
"_enableNewTabForExternalLink": "true",
"_disableContribution": "true",
"_appFooter":"demo",
"_appLogoPath": "../images/image.png",
"_appFaviconPath": "../images/favicon.png",
"_language": "fr",
"pdf": true,
"pdfTocPage": true,
"pdfCoverPage":"./pdf/cover.html",
"pdfFooterTemplate":"./pdf/footer.html"
},
```
My footer.md file are the default content, my footer.html is present but all my pdf file have in footer the path "/pdf/footer.html"
and not the content of footer.html.

**Context (please complete the following information):**
- OS: Windows
- Docfx version: 2.75.0