[TEST ONLY] APIv4 - Remove unused extras from ConformanceTest

[colemanw]

Overview

Cleans up the APIv4 Conformance test to remove the not-useful TransactionalInterface (broken because this test creates custom data) and the unused OptionCleanupTrait (which never called its tearDown method so did nothing).

[civibot]

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[colemanw]

Merging. (it's just unit tests, and they pass)