Issue Summary

When the language is set as English(UK) under Account preference, we cannot see Monday as the starting working day in the date-time picker field under Sprint planning / Backlog

Steps to Reproduce

1. Set the language to  English(UK) under Account preference, you will see all the date-time picker fields have Monday as the first working day.
   
2. But, when you try to set the sprint date in the sprint modal or add dates for Sprints under the Backlog section you will see Sunday as starting date. Please refer to the below screenshot.

Expected Results

All the date-time picker field should Monday as first working days 

Actual Results

It is showing Sunday as the first working day.

Workaround

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