SimpleDateChooser day value is always changed to 1 when month is chosen

[karendolan]

To duplicate:

• set SimpleDateChoose with a date
• just change the month/year
• EXPECTED: only the month/year is changed
• ACTUAL: the day of month is changed to "1"

This line always sets the days[0] instead of preferring existing day value, and only setting day[0] if no day was previously set.

https://github.com/harvard-edtech/dce-reactkit/blob/main/src/components/SimpleDateChooser.tsx#L154

This line only sets the day, and doesn't forced change the month/year like the day is being changed above.

dce-reactkit/src/components/SimpleDateChooser.tsx

Lines 213 to 221 in c2bd4c7

	onChange={(e) => {
	// Only change the day
	onChange(
	month,
	Number.parseInt(e.target.value, 10),
	year,
	);
	}}
	>