ci: Remove nlohmann-json from Fedora base image

Revert commit f24c6ae5b8 (ci: Add nlohmann-json to Fedora base image,
2023-05-17).  The previously-upcoming dependency on nlohmann-json has
been replaced with our existing dependency on jsoncpp.

.gitlab/ci/docker/fedora37/deps_packages.lst

@@ -19,7 +19,6 @@ make
 bzip2-devel
 expat-devel
 jsoncpp-devel
-json-devel
 libarchive-devel
 libcurl-devel
 libuv-devel