Allow to persist cascade for non-null embedded id

[dstepanov]

Fixes #1173

[Chris-V]

@dstepanov Thanks a lot for taking charge of this. I tested your fix in my project and am now facing the second issue I described in #1173 regarding the dialect. Notice the first query quotes columns with backticks, but the second uses double quotes.

Logs:

10:01:12.658 [Test worker] DEBUG io.micronaut.data.query - Executing SQL Insert: INSERT INTO `organization` (`id`,`name`) VALUES (?,CONVERT(? USING UTF8MB4))
10:01:12.875 [Test worker] DEBUG io.micronaut.data.query - Executing Batch SQL Insert: INSERT INTO "organization_profile" ("organization_id","profile_name") VALUES (?,?)

Stack trace

SQL Error executing INSERT: SQL error executing INSERT: (conn=6) You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '"organization_profile" ("organization_uuid","profile_name") VAL' at line 1
io.micronaut.data.exceptions.DataAccessException: SQL Error executing INSERT: SQL error executing INSERT: (conn=6) You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '"organization_profile" ("organization_id","profile_name") VAL' at line 1
	at app//io.micronaut.data.runtime.operations.internal.AbstractRepositoryOperations.persistOne(AbstractRepositoryOperations.java:289)
	at app//io.micronaut.data.jdbc.operations.DefaultJdbcRepositoryOperations.lambda$persist$16(DefaultJdbcRepositoryOperations.java:753)
	at app//io.micronaut.transaction.support.AbstractSynchronousTransactionManager.executeWrite(AbstractSynchronousTransactionManager.java:175)
	at app//io.micronaut.data.jdbc.operations.DefaultJdbcRepositoryOperations.persist(DefaultJdbcRepositoryOperations.java:751)
	at app//io.micronaut.data.runtime.intercept.DefaultSaveEntityInterceptor.intercept(DefaultSaveEntityInterceptor.java:45)
	at app//io.micronaut.data.intercept.DataIntroductionAdvice.intercept(DataIntroductionAdvice.java:114)
	at app//io.micronaut.data.intercept.DataIntroductionAdvice.intercept(DataIntroductionAdvice.java:88)
	at app//io.micronaut.aop.chain.MethodInterceptorChain.proceed(MethodInterceptorChain.java:137)

Edit: I enabled ANSI_QUOTES on my test setup and the patch works. However this is not an option for our production environment :(