[TD-4035]<fix>: taosdemo more checking for prevent value out of scope. (#5992)

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

change min rows and max rows to unsigned int and 0 means default.

* [TD-4035]<fix>: taosdemo more checking for prevent value out of scope.

change offset=0 to get all childtable count
Co-authored-by: NShuduo Sang <sdsang@taosdata.com>