Block Import: move worldstate head only if import successful

[macfarla]

PR description

Block importer was previously advancing the head for the world state by default.

This method is only used by backward sync context and rlp block importer. It works directly on the head world state.

This PR introduces a check so that the worldstate only updates head if the block processing (import) was successful. This then matches how the scenario would play out when driven by the Engine API.

Fixed Issue(s)

This fixes a hive test that uses RLPBlockImporter to set up a specific scenario checkGasLimit_Cancun

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• 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:

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

[Gabriel-Trintinalia]

LGTM