TST: test_constructors.py::TestSeriesConstructors::test_constructor_dtype_datetime64

[simonjayhawkins]

xref #24812 (comment). follow-up PR required.

[charlesdong1991]

should it then raise a TypeError?

[gfyoung]

@charlesdong1991 : It looks the correct error is raised, but the message is not quite right.

[charlesdong1991]

yeah, will take a closer look @gfyoung