Allow any @Transactional propagation for @TransactionalEventListener with BEFORE_COMMIT phase

[carsago]

Following discussions in #30679 and #31414, validation was added to restrict @TransactionalEventListener to only use @Transactional(propagation = Propagation.REQUIRES_NEW) or @Transactional(propagation = Propagation.NOT_SUPPORTED).

However, this validation is unnecessary when the @TransactionalEventListener phase is BEFORE_COMMIT (excluding propagation NEVER). While removing the @Transactional would solve the issue, this creates unnecessary friction when upgrading Spring versions.