Due to the static build, libcharon will depend on libradius as soon as
eap-radius is enabled even if not actually used. So in order to avoid
breaking the build of fuzz_ike when enabling this in CIFuzz, enable
it now before adding the actual fuzzer.
Closesstrongswan/strongswan#3028
Signed-off-by: Arthur Chan <arthur.chan@adalogics.com>