Fix faulty INSERT test query from the templated benchmark example introduced in #386 since it results in duplicate keys

[bpkroth]

Need to fix INSERT test query from the templated benchmark example introduced in #386 since it results in duplicate keys.

Originally posted by @bpkroth in https://github.com/cmu-db/benchbase/pull/427#discussion_r1427201975

[bpkroth]

@ETHenzlere can you please take a look at this?

[bpkroth]

@anjagruenheid for visibility

[bpkroth]

See Also: https://github.com/cmu-db/benchbase/pull/427/commits/7d4e90b2b6fd72eaf86dc4669da594768a7ff8c0