Multi tenancy with multiple datasources is not working

If I add "implements MultiTenancy" to the domain class, it tries to use default datasource instead of the one defined in the datasource mapping field and then it returns a table not found error.

If I remove "implements MultiTenant" or remove the multiple databases setup, everything works fine.

```
class SystemTransaction implements MultiTenant {
static mapping = {
datasource 'accountTransaction'

18:51:05.0222 [http-nio-8080-exec-9] DEBUG o.s.j.d.DataSourceUtils - Fetching JDBC Connection from DataSource
18:51:05.0239 [http-nio-8080-exec-9] DEBUG o.h.e.j.s.SqlExceptionHelper - could not extract ResultSet [n/a]
java.sql.SQLSyntaxErrorException: Table 'gaming.system_transaction' doesn't exist
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:916)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeQuery(ClientPreparedStatement.java:972)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.apache.tomcat.jdbc.pool.StatementFacade$StatementProxy.invoke(StatementFacade.java:118)
at jdk.proxy2/jdk.proxy2.$Proxy153.executeQuery(Unknown Source)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.extract(ResultSetReturnImpl.java:57)
at org.hibernate.loader.Loader.getResultSet(Loader.java:2322)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:2075)
at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:2037)
at org.hibernate.loader.Loader.doQuery(Loader.java:956)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:357)
at org.hibernate.loader.Loader.doList(Loader.java:2868)
at org.hibernate.loader.Loader.doList(Loader.java:2850)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2682)
at org.hibernate.loader.Loader.list(Loader.java:2677)
at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:109)
at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1917)
at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:370)
at org.grails.orm.hibernate.query.AbstractHibernateCriteriaBuilder.invokeMethod(AbstractHibernateCriteriaBuilder.java:1699)
at org.grails.orm.hibernate.query.AbstractHibernateCriteriaBuilder.list(AbstractHibernateCriteriaBuilder.java:1570)
at org.grails.datastore.mapping.query.api.BuildableCriteria$list$0.call(Unknown Source)

```

Start with the SystemTransaction domain class and its static mapping for the accountTransaction datasource, then reproduce the MultiTenancy setup with multiple datasources. Trace why the query selects the default datasource; done means the multi-tenant query uses accountTransaction and no longer reports that gaming.system_transaction is missing.

Written by the indexing model from the issue text.