test(hibernate7): register domain classes in the two specs the TCK API now requires

Completes the PR-C mirror. The merged GrailsDataTckManager makes domainClasses a
private set with an empty default, so every spec must register the classes it
uses via registerDomainClasses(...). The earlier mirror migrated the 27 specs
using manager.domainClasses.addAll([...]), but two specs used other patterns and
were missed - the full pre-PR test run surfaced them:

- HibernateOptimisticLockingSpec had no setupSpec (it relied on the old manager's
  non-empty default set). Added setupSpec registering OptLockVersioned and
  OptLockNotVersioned, matching Hibernate5OptimisticLockingSpec.
- HibernateValidationSpec used `manager.domainClasses += [...]` (compound-assign,
  now a ReadOnlyPropertyException). Switched to registerDomainClasses(...) with
  the full class list (TestEntity, ChildEntity included, since the default is
  empty), matching the hibernate5 HibernateValidationSpec.

Verified: ./gradlew :grails-data-hibernate7-core:test now passes
(571 tests, 0 failures, 26 skipped); all four violation reports are clean.

Assisted-by: claude-code:claude-opus-4-8

Author: jamesfredley

grails-data-hibernate7/core/src/test/groovy/grails/gorm/tests/HibernateOptimisticLockingSpec.groovy

@@ -29,6 +29,10 @@ import org.grails.orm.hibernate.support.hibernate7.HibernateOptimisticLockingFai
  */
 class HibernateOptimisticLockingSpec extends GrailsDataTckSpec<GrailsDataHibernate7TckManager> {
 
+    void setupSpec() {
+        manager.registerDomainClasses(OptLockVersioned, OptLockNotVersioned)
+    }
+
     void "Test optimistic locking"() {
 
         given:

grails-data-hibernate7/core/src/test/groovy/grails/gorm/tests/HibernateValidationSpec.groovy

@@ -32,8 +32,8 @@ import org.springframework.transaction.support.TransactionSynchronizationManager
  */
 class HibernateValidationSpec extends GrailsDataTckSpec<GrailsDataHibernate7TckManager> {
     void setupSpec() {
-        manager.domainClasses += [ClassWithListArgBeforeValidate, ClassWithNoArgBeforeValidate,
-                                 ClassWithOverloadedBeforeValidate]
+        manager.registerDomainClasses(ClassWithListArgBeforeValidate, ClassWithNoArgBeforeValidate,
+                                 ClassWithOverloadedBeforeValidate, TestEntity, ChildEntity)
     }
 
     void "Test that validate works without a bound Session"() {