(App) - detect missing Quarto sooner

[StijnKas]

Is your feature request related to a problem?

We detect missing dependency for Pandoc in the first page of the healthcheck app, but only check for Quarto while generating the health check

Describe the solution you'd like

I would like to check for Quarto in the first page too - so we can warn about these two system-wide packages and make it easier to understand missing dependencies

Describe alternatives you've considered

Additional context