Analytics - End date for get_change_over_time_df should be inclusive

[jpaten]

• Currently the end date for get_change_over_time_df is excluded from the date range, so if the time dimension is yearMonth the end date must be after the last month to be included in the report. This is inconsistent with get_flat_data_df, where the last day is included in the report, making the functions in sheets_element more confusing than necessary