Ember's legacy mixin system does not support native-class syntax, so we have to use the non-decorator syntaxes for `action()` and `computed()`.
Eventually, we will need to refactor things to remove these mixins... but today is not that day.
Prior to this fix, weekly could be 8 days and we could have differences between period chooser text and actual results in the chart.
A good followup to this PR would be to add custom date ranges in period-chooser component.