### Bug description

When inside a project such as a website, if the last document to be rendered includes `embed-resources: true`, the shared "libs" is embedded, thus is missing for the project.

Behaviour initially discovered in #5738.

`embed-resources` should raise a warning and be ignored inside a Quarto project.

### Steps to reproduce

````sh
cat << EOF > _quarto.yml
project:
  type: website

website:
  title: "Quarto-project-embed-resources"
  navbar:
    left:
      - href: index.qmd
        text: Home
      - zzz.qmd
      
EOF

cat << EOF > index.qmd
---
title: "Quarto-project-embed-resources"
---

This is a Quarto website.

To learn more about Quarto websites visit <https://quarto.org/docs/websites>.

EOF


cat << EOF > zzz.qmd
---
title: 'Reveal.js Presentation'
format: revealjs
embed-resources: true
---

## Slide

EOF
````

```sh
quarto render
```

### Expected behavior

```
tree _site -L 2
_site
├── index.html
├── search.json
├── site_libs
│   ├── bootstrap
│   ├── clipboard
│   ├── quarto-html
│   ├── quarto-nav
│   ├── quarto-search
│   └── revealjs
└── zzz.html

8 directories, 3 files
```

### Actual behavior

```
tree _site -L 2
_site
├── index.html
├── search.json
└── zzz.html

1 directory, 3 files
```

### Your environment

- VSCode Insiders
- macOS Ventura 13.4

### Quarto check output

<img width="1111" alt="image" src="https://github.com/quarto-dev/quarto-cli/assets/8896044/3fed9b29-585b-4db5-9c00-5260af2b8afb">

dragonstyle
2023-05-30T16:56:16Z
mcanouil
bug triaged-to
v1.4
open
`embed-resources: true` in a project causes "shared" `libs` to be embedded
https://github.com/quarto-dev/quarto-cli/issues/5748