Issue Summary

In Board settings>>under Working Days,

give an option to set the starting day in the Sprint calendar dropdown to other days like Monday or Tuesday etc. 
Right now, in Sprint create or edit modal, while setting the Sprint end date & Start date, we get Sunday as the start of the week:

Currently following this article: https://confluence.atlassian.com/jirakb/how-to-set-monday-as-first-day-of-week-in-date-picker-calendar-604209836.html Or by setting the Language in your Account preference we can only change the start day of Date Picker fields on the issue view. 

Steps to Reproduce

1. goto Backlog of Scrum project.
2. Create a Sprint.
3. Set the Sprint start & End date.
4. You will see the start day of the week as Sunday. 

Expected Results

We should have the option to change the start day of a week in the Sprint start & end date dropdown calendar. 

Actual Results:

1. You will see the start day of the week as Sunday. 

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available