Removing ping_interval_ms from network/src/validator_network/network_builder.rs
Removing ping_interval_ms from network/src/validator_network/network_builder.rs

Closes: #4193
Approved by: davidiw

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