Increase validator active set to 75

To further decentralize the Axelar validator set and continue growing the network, we're increasing the active set in batches of 5 to maintain network health and allow time for validators to onboard and register for EVM connections. This proposal increases validator active set to 75, which will hit the original goal of expanding validator set to 75 as discussed here: https://community.axelar.network/t/signaling-proposal-to-update-validators-set-size-inflation-rates/2190