internal/ethapi: add optional parameter for blobSidecars

[zlacfzy]

Description

Make the param showBlob optional, user don't need change the way to query blobs, even if they don't add the bool param it work as before.

Rationale

tell us why we need these changes...

Example

The two way both works now.

{"jsonrpc":"2.0","method":"eth_getBlobSidecars","params":["latest", false],"id":1}]'
{"jsonrpc":"2.0","method":"eth_getBlobSidecars","params":["latest"],"id":1}]'

Changes

Notable changes:

• add each change in a bullet point here
• ...

[Zionsammy]

contracts/helpers/VerifierCaller.sol