bug#71849: pdflatex.fmt error using pandoc/pdflatex

[Antero Mejr]

When using pandoc to export markdown to PDF, the following error occurs:

```
kpathsea: Running mktexfmt pdflatex.fmt
mktexfmt: No such file or directory

kpathsea: Running mktexfmt pdflatex.fmt
mktexfmt: No such file or directory
Error producing PDF.
This is pdfTeX, Version 3.141592653-2.6-1.40.25 (TeX Live 2023/GNU Guix) 
(preloaded format=pdflatex)
 restricted \write18 enabled.
I can't find the format file `pdflatex.fmt'!
```

It appears that the texlive packages were refactored lately, so it is
difficult to tell what packages are needed. Currently the following
packages are installed:

texlive-base
texlive-bin
texlive-scripts
texlive-latex-base

Also I think the pandoc package should propagate the packages it needs
to build PDFs.