[Bugfix] Fix date-handling bug when today's date is later than the target month

[marc-hughes]

If today's date has a date-part that's bigger than the number of days in the target month, you could not set the schedule to that date because of the way the Date object validates dates.

Explanation of bug:

const d = new Date(); // ex: Date is 1/30/2024
d.setFullYear(2025) // Date is now 1/30/2025
d.setMonth(2); // Date tries to be 2/30/2025, which doesn't exist, and rolls over to 3/1/2025
d.setDate(15); // Date is now 3/15/2025 instead of 2/15/2025 as expected

[tzs]

Possible dumb question since I have had very little occasion to use the Date class and so am probably missing something obvious, but it looks like all these places are creating a new Date object and initializing it to the same date/time as an existing date object.

Couldn't they all be replaced by using the form of the Date constructor that takes an existing date object? E.g., targetStartDate = new Date(startDate)?