Fix incorrect field name in Deneb `BuilderBid` type

[jimmygchen]

I've just noticed that the field names in the BuilderBid schema doesn't match the SignedBuilderBid example JSON:

https://github.com/ethereum/builder-specs/blob/0d039df6cbe8af9ff16a1546281064d41638b5e6/examples/deneb/signed_builder_bid.json#L24-L28

• I've updated the field name to blinded_blobs_bundle to match the example. (I think this name also reflects the structure better)
• Fixed the ordering of the fields in the example to match the schema, i.e. blob_roots comes last in blinded_blobs_bundle