Provide end_time for active choice month if not unlocked

[UncleGoogle]

Active sub. content ends next month-first Friday at 10 PT.

This may be useful:

def find_first_friday(y, m):
    dt = datetime.date(y, m, 1)
    next_friday = (1 + (4 - dt.weekday())) % 7
    dt.replace(day=next_friday)
    return dt

or

"navbarOptions": {"activeContentEndDate|datetime": "2020-06-05T17:00:00"

from webpack marketing_data in humblebundle.com/subscription

Currently Galaxy not uses this info yet.