Refactor setupNetworkProviders as it affects when forking a chain

function setupNetworkProviders(hardhatConfig) {
  for (const netConfig of networkConfigs) {
    hardhatConfig.networks[netConfig.network] = {
      chainId: netConfig.chainId,
      url: netConfig.url ? netConfig.url : getDefaultProviderURL(netConfig.network),
      gas: netConfig.gas || 'auto',
      gasPrice: netConfig.gasPrice || 'auto',
      accounts: {
        mnemonic: getAccountMnemonic(),
      },
    }
  }
}

The accounts entry affects how hardhat verifies that a sending account is a hosted private key.

Start by locating setupNetworkProviders and the networkConfigs it consumes. Trace how the accounts entry is used during chain forking and how sending accounts are classified, then define tests that demonstrate the intended fork behavior and hosted private-key verification before refactoring.