fcl-db: sqldb: some databases supports inserting of explicit values into "autoincrementing" columns. So in case when ftAutoInc field has already supplied value, do not do fetch of LastID

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@29237 3ad0048d-3df7-0310-abae-a5850022a9f2