Fix BlockNumberOrHash usage

[elmattic]

Describe the bug

getTipsetByEthBlockNumberOrHash is a function in Lotus used to retrieve a tipset. It accepts predefined strings such as "pending" or "latest". However, using "earliest" will result in an error.

This function is utilized in several Ethereum endpoints:

• EthGetTransactionCount
• EthGetBlockReceiptsLimited
• EthGetCode
• EthGetStorageAt
• EthGetBalance
• EthEstimateGas
• EthCall

In Forest, a similar function exists called tipset_by_block_number_or_hash. The key difference is that Forest also supports additional predefined strings such as "safe" and "finalized".

This function is used by:

• EthGetTransactionCount
• EthGetCode
• EthGetStorageAt
• EthGetBalance
• EthEstimateGas
• EthCall

And

• EthFeeHistory
• EthGetBlockByHash
• EthGetBlockByNumber
• EthGetTransactionByBlockNumberAndIndex
• EthTraceBlock

For the second list of functions, support for "safe" and "finalized" might be required. However, Forest is likely to diverge from Lotus in the first list.

To address these differences, we should:

1. Use clear types: Split the Predefined type into subtypes where necessary. For instance, functions like EthGetBlockByNumber should only accept the required subtype (e.g., a hexadecimal block number).

2. Expand API coverage: Ensure the API supports all possible values for predefined strings, including both accepted and rejected values, to improve robustness and compliance with the specification. This is especially important for defining a Common Node API and an OpenRPC specification.

Environment (please complete the following information):

• OS:
• Branch/commit
• Hardware

Other information and links