Having several sprints overlapping will make seeing issues in a plan impossible when grouping by teams

Issue Summary

If you have a plan grouped by team with multiple sprints that overlap on time, it will create a timeline header which heigh is greater than the screen itself, therefore, the issues below it won't be visible. If you try to scroll, it will seem as it doesn't work, but in reality, the header transforms into a "sticky" header and becomes visible always.

Steps to Reproduce

1. Create a plan.
2. Create a team and associate it with the plan.
3. Associate an issue source in the plan with the team.
4. Create multiple sprints with the same start date and end date (or that the overlap at least one day)
5. Go to the plan, go to View Settings and group by Team.
6. Enable the checkbox "Show capacity in timeline"
7. You should see the plan and all the sprints in the timeline
8. Try to scroll down to see the issues.

Expected Results

You should be able to scroll and see the issues

Actual Results

The timeline can't be scrolled and the scrollbar disappears

Workaround

Disable the "Show capacity on timeline" to hide the sprints, or group by something else to load the plan properly.