Removing is_empty from network/network-address/src/lib.rs
Removing is_empty from network/network-address/src/lib.rs

Closes: #4340
Approved by: huitseeker

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