 Updated `test_sort()` and `test_sort_counts()`
 Updated `test_sort()` and `test_sort_counts()`

Updated `test_sort()` in class `TestLightcurve` to check if `sort()` works with new attributes. Removed similar test from class `TestNewPeraSupport`. Updated `test_sort_counts()`  similarly.

StingraySoftware/stingray