Fix eth_getBlockByNumber with empty params returns

[iryoung]

PR description

This PR addresses a bug in the eth_getBlockByNumber method, where invoking it with empty parameters results in the error message "Invalid block, unable to parse RLP".

There're some consideration while I investigate & fix the bug

• I would have preferred to use the message proposed in the issue; however, a pre-defined error message better fits this situation, so I opted to use it.

• Adding data would require modifications to org.hyperledger.besu.ethereum.api.jsonrpc.execution.BaseJsonRpcProcessor.process(), which is outside the scope of this fix.

• The message for RpcErrorType.INVALID_BLOCK_PARAMS might seem slightly inconsistent, but adjusting it is also beyond the scope of this PR.

• Request

POST http://localhost:8545
Content-Type: application/json

{"jsonrpc":"2.0","id":"53","method":"eth_getBlockByNumber","params":[]}

• Before

{
  "jsonrpc": "2.0",
  "id": "53",
  "error": {
    "code": -32602,
    "message": "Invalid block, unable to parse RLP"
  }
}

• After

{
  "jsonrpc": "2.0",
  "id": "53",
  "error": {
    "code": -32602,
    "message": "Invalid block number params"
  }
}

Fixed Issue(s)

fixes #7918

Thanks for sending a pull request! Have you done the following?

• Checked out our contribution guidelines?
• Considered documentation and added the doc-change-required label to this PR if updates are required.
• Considered the changelog and included an update if required.
• For database changes (e.g. KeyValueSegmentIdentifier) considered compatibility and performed forwards and backwards compatibility tests

Locally, you can run these tests to catch failures early:

• unit tests: ./gradlew build
• acceptance tests: ./gradlew acceptanceTest
• integration tests: ./gradlew integrationTest
• reference tests: ./gradlew ethereum:referenceTests:referenceTests