Created multi-shift events are 1 hour off

[xela1601]

Description

Created multi-shift event are shifted by 1 hour.

The bug

When creating a new event in the week overview of a projects calendar by clicking on "Create multiple events that form shifts", the created event is 1 hour off after creating. So it starts and ends 1 hour after the user intended it to start and end.

Steps to reproduce

1. Go to https://app.dev.zetkin.org/organize/1/projects/51/calendar?timeScale=week to open the calendar week view of a specific project
2. Select a timespan by drag and drop on a day column within the calendar
3. Click on "Create multiple events that form shifts"
4. publish the multi-shift event by clicking the publish button

Expected Behaviour

The created multi-shift event starts and ends exactly as selected by the user via drag and drop (Step 2)

Actual Behaviour

The created multi-shift event starts and ends 1 hour after selected by the user.

Screenshots

Drag and drop from 1:00 AM -> 5:00 AM

The created event is between 2:00 AM -> 6:00 AM

[mathiaswiench]

Would like to work on this :)