XArray IO can only select time at daily intervals

[ghidalgo3]

Problem description

In xarray.io.get_variable, if the datetime argument is an ISO8601 datetime like 2025-02-25T15:33:38Z with a date and a time, the time part of the datetime is dropped. This causes a problem for assets whose temporal dimension is more frequent than daily, because get_variable will always snap to the nearest day.

I think the fix is to simply remove the split by T and keep datetime intact.

titiler/src/titiler/xarray/titiler/xarray/io.py

Lines 175 to 187 in 28d33a6

	# TODO: Technically we don't have to select the first time, rio-tiler should handle 3D dataset
	if "time" in da.dims:
	if datetime:
	# TODO: handle time interval
	time_as_str = datetime.split("T")[0]
	if da["time"].dtype == "O":
	da["time"] = da["time"].astype("datetime64[ns]")
	da = da.sel(
	time=numpy.array(time_as_str, dtype=numpy.datetime64), method="nearest"
	)
	else:
	da = da.isel(time=0)