chore(derive): Ethereum Data Source Tests

[refcell]

Description

Warning

This is blocked by #159

Add unit tests for the EthereumDataSource.

These tests will need to use mock/test chain providers and blob providers for constructing the data source.

They should validate when open_data is called that

• if the ecotone_timestamp is not set and a calldata source should be returned.
• if the ecotone_timestamp is set and the block_ref timestamp is prior to the ecotone_timestamp, a calldata source is created.
• if the ecotone_timestamp is set and the block_ref timestamp is greater than or equal to the ecotone_timestamp, a blob provider is created.