lang/erlang: Update to 28.5.0.2
OTP 26 is end-of-life; move the main suite to OTP 28. Update the bundled
erl_interface, snmp and tools subsystem versions, and bump the corba
dependency to 5.2.2.
Drop the FOP and PDF options: they relied on the XML/fop documentation
toolchain that upstream removed in OTP 27, so they no longer build.