simulators/eth2/dencun: Fixes to builder tests

[marioevz]

Changes included

• Builder tests now wait until all clients' builders have proposed at least one block with blobs, because some tests were erroneously failing during the verification phase.
• Bumped the Dencun fork epoch on the builder tests for clients that do not require finalization, since nimbus was now taking one epoch before starting to request payloads from the builder, which resulted in a test fail.
• Use fix in simulators/ethereum/engine: TransactionCreator - Keep track of blobs #1030 to keep track of the blobs in the blob spammer used by all eth2/dencun tests, which resulted in the blob KZG cache not being used due to the blob IDs being too high