[LBT] Remove DISABLE_FN_UPGRADE from compat LBT
[LBT] Remove DISABLE_FN_UPGRADE from compat LBT

DISABLE_FN_UPGRADE was a temporary measure for compat test due to limitations of config builder based setup.

This PR removes DISABLE_FN_UPGRADE as at this point it actually hurts us

Closes: #5656

aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,libra/libra,libra/libra,aptos-labs/aptos-core