fix(query): split query should be able to run when step > (end - start)

[Boyuan-Yu]

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• Tests for the changes have been added (for bug fixes / features) ?
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Current behavior :
When we have a query that cross the namespace migration point, it's trying to stitch two series from two partitions. The first partition gives the time range (start, start + step), the end time of this range is larger than the end time of the query so it gives this error:

"requirement failed: start 1724457600000 should be <= end 1724457599000"

New behavior :
The query has one exec plan for the partition before the split. No need to stitch.