Fix ExpandableCalendar StartHeight calculations

[KimGnab]

Problem Cause:
When ExpandableCalendar was configured with initialPosition={Positions.OPEN}, the calendar's total open height startHeight was calculated before the actual height of the header section headerHeight was determined. This led to headerHeight being treated as 0 or an incorrect value, causing the calendar content to appear clipped or the layout to be misaligned, even though the calendar was in an open state.

Solution:

1. Fixed that when the headerHeight value changes, the logic that calculates the height when the calendar is open getOpenHeight immediately reflects this and recalculates the startHeight correctly.
2. Also, synchronize the correctly calculated startHeight value to the object that manages native component styles internally _wrapperStyles to ensure the correct height is applied to the actual UI.

#2646