Fix AlchemyGlobalContext Default Value Initialization

[Hopium21]

Changed: alchemyProvider: new Alchemy() → alchemyProvider: new Alchemy({ apiKey: '', network: Network.ETH_MAINNET }) Reason: The new Alchemy() constructor requires an apiKey and network for proper initialization. Without these values, it may cause runtime errors. This change ensures that the default context value is correctly instantiated with valid settings.