Support switching off state overrides via an environment variable

[prabhatverma286]

Hardhat and ganache forks currently dont support state overrides. When running this library with a fork, we get execution revert whenever using the chainId as mainnet.

More details can be found here: https://stackoverflow.com/a/75823265/7655219

Would be nice to control the state overrides behaviour using an environment variable

[BobTheBuidler]

This sounds like an agreeable change. If you go ahead and put together a PR for this, I can review it and get it merged.
Thanks