#15763 Fix bug Oralce MV changes are not saved (#15764)

* #15763 Fix bug Oralce  MV changes are not saved

Any changes in Oracle MV can not be saved when switch to DDL Compact Format. But it works well when switch to Full DDL Format.

* #15763 Fix bug Oralce MV changes are not saved 

remove unnecessary class cast operation

* #15763 Fix bug Oralce MV changes are not saved

Delete unnecessary validation

plugins/org.jkiss.dbeaver.ext.oracle/src/org/jkiss/dbeaver/ext/oracle/edit/OracleMaterializedViewManager.java

@@ -59,9 +59,6 @@ public class OracleMaterializedViewManager extends SQLObjectEditor<OracleMateria
         if (CommonUtils.isEmpty(command.getObject().getName())) {
             throw new DBException("View name cannot be empty"); //$NON-NLS-1$
         }
-        if (CommonUtils.isEmpty(command.getObject().getObjectDefinitionText(monitor, options))) {
-            throw new DBException("View definition cannot be empty"); //$NON-NLS-1$
-        }
     }
 
     @Nullable