Fix: removed time filter test on technology

Removes an unnecessary test that checks whether return technology records have a valid_timestamp_start above a certain data.

[x] Dependencies install correctly in a clean environment and code executes;
[x] Test coverage extended; created tests fail without the change (if possible);
[x] All tests passing;
[x] Commits follow a type convention (e.g. https://gist.github.com/brianclements/841ea7bffdb01346392c#type);
[x] Extended the README, documentation and/or docstrings, if necessary;

transition-zero / tz-client