omci-lib-go: Fast Channel Configuration Profile ME missing Managed Entity ID attribute

While creating a unit test to validate all attribute names are valid and present in generated golang OMCI code it was discovered that the Fast Channel Configuration Profile ME had a code generation error due to the Entry not being properly defined in the ITU G.988 specifications.

While this Managed Entity is not currently used by VOLTHA, the JSON class/attribute validation unit test will be used to verify the attribute string constants that will be added to omci-lib-go for @VOL-4485.

Once this is merged, the plan is to code-generate the managed entities with attribute names as constant string variables for the OpenONU device adapter (and bbsim if interested).