restrict the linkage of the time range

[tigertriggertimer]

Use case

1、There is some stutter when scrolling the first time picker;
2、In some cases, the time period may be cross-day, such as from 15:00 today to 13:00 tomorrow, but not allowed to select a former time.

Proposal

Add a parameter to range picker to prevent the check "if (initialSecondDateTime!.isBefore(date)) {" in range_picker.dart

Or I can fork and update Bottom-Picker, but if relevant parameters can be added to support this feature, it would be much more convenient for many users.
And I will be very appreciate.