[time series] Add Time series inputs tests (#21846)
* intial test of inputs
* added test for generation
* remove asserts
* fixed test
* Update tests/models/time_series_transformer/test_modeling_time_series_transformer.py
Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>
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Co-authored-by: NielsRogge <48327001+NielsRogge@users.noreply.github.com>