Make calendar calculateDurationMs project independent

[marciogurka]

Forum post

"Hello!

Currently porting calendar functionality from an older version of Bryntum and have a small feature request. We are using the calendar independently of any project, as a way to use the duration calculation methods. In the current Bryntum version that is not possible because of the way it checks for 'adjustDurationToDST' in the calculateDurationMs method

            const adjustDurationToDST   = this.getProject().adjustDurationToDST

If that could be optionally chained, even better with a fallback set as a parameter during the calendar initialization, that would be extremely helpful."

[gismya]

To clarify, the easiest solution would be to simply change the quoted row to
const adjustDurationToDST = this.getProject()?.adjustDurationToDST ?? false; like you do in accumulateWorkingTime. That would definitely be enough. The suggestion to add a DST adjustment option to the calendar init was mostly a random thought I got at the same time and not something I have any known use for at the moment.