Take astropy Time as input to `split_series_using_lytaf`

[dstansby]

Describe the feature

The first parameter of split_series_using_lytaf says:

timearray ([numpy.ndarray](https://numpy.org/doc/stable/reference/generated/numpy.ndarray.html#numpy.ndarray)) – An array of times understood by sunpy.time.parse_time.

Since astropy Time objects can contain multiple times, I think it would be better for integration purposes to just accept an astropy time here instead of a numpy array of times (eww)

Proposed solution

No response