dino: remove unnecessary private transitive deps

As explained by Orivej (reformatted from Markdown):

> These (except libsignal-protocol-c) are private dependencies of the
> actual dependencies that should neither be propagated nor added
> manually to dino. For example, libpsl and brotli come from
> libsoup-2.4.pc:
>
>     Requires: glib-2.0 >=  2.38, gobject-2.0 >=  2.38, gio-2.0 >=  2.38
>     Requires.private: libxml-2.0, sqlite3, libpsl >=  0.20, libbrotlidec, zlib
>
> (To be precise, glib uses utillinuxMinimal rather than utillinux.)
>
> The warnings we see, such as Package 'mount', required by 'gio-2.0',
> not found, come from CMake running both pkg-config --libs and
> pkg-config --static --libs to populate both <XXX>_LIBRARIES and
> <XXX>_STATIC_LIBRARIES[1], but dino has no use for the latter.
> Currently these warnings can not be disabled:
> https://gitlab.kitware.com/cmake/cmake/issues/18158
>
> (They could be prevented by pruning Requires.private from shared-only
> libraries akin to <https://github.com/NixOS/nixpkgs/pull/51767>,
> although it can not be detected if a library is shared-only from the
> .pc file alone, and this is just a warning.)
>
> [1]: docs: https://cmake.org/cmake/help/v3.16/module/FindPkgConfig.html