Fix: Indexing with dates of higher resolution should return empty

[suzyahyah]

Indexing with out of range datetime objects of higher resolution should return empty slice instead of raising KeyError.

This is to be "consistent with normal slicing, where out of range slice bounds return an empty object, and don't raise an error".

As per this issue 25803, specifically #25803 (comment), if the date is of higher resolution than the current object in the series, e.g., day>minutes, then the empty slice should be returned instead of KeyError.

• closes Should DatetimeIndex indexing with strings ever raise KeyError? #25803 (Replace xxxx with the GitHub issue number)
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