Add missing pdf preview dependency. `ctpv` uses `pdftoppm` [1] to
preview pdf files. Required dependency was not included on the last PR
targeting `ctpv`, although it added the tools for other ftypes [2].
Fix chafa image privews by passing the missing flag via a patch. This
comes from a year long bug fix PR open at upstream, for details refer
there [3].
[1]: 4efa0f976e/README.md (L58)
[2]: github:NixOS/nixpkgs#223487
[3]: github:NikitaIvanovV/ctpv#90
d16d20a4f5