misc/libmodulemd: drop unused Meson options after 8e0304d612f2

meson.build:12:0: ERROR: Unknown options: "developer_build, skip_formatters"

https://github.com/fedora-modularity/libmodulemd/commit/1096cda67bbb

PR: 259080
Reported by: antoine (via exp-run)
Regressed by: https://github.com/mesonbuild/meson/commit/dbf2ace6ca1c