Why is Competitor Sales a Positive Contribution?

## Project Robyn

## Describe issue
I am running the demo and see that in the response decomposition waterfall by predictor, competitor sales is the largest contribution. Why would competitor sales be the largest contribution, shouldn't it be negative?

## Provide reproducible example
This is the input directly from the demo:
InputCollect <- robyn_inputs(
dt_input = dt_simulated_weekly,
dt_holidays = dt_prophet_holidays,
date_var = "DATE", # date format must be "2020-01-01"
dep_var = "revenue", # there should be only one dependent variable
dep_var_type = "revenue", # "revenue" (ROI) or "conversion" (CPA)
prophet_vars = c("trend", "season", "holiday"), # "trend","season", "weekday" & "holiday"
prophet_country = "DE", # input country code. Check: dt_prophet_holidays
context_vars = c("competitor_sales_B", "events"), # e.g. competitors, discount, unemployment etc
paid_media_spends = c("tv_S", "ooh_S", "print_S", "facebook_S", "search_S"), # mandatory input
paid_media_vars = c("tv_S", "ooh_S", "print_S", "facebook_I", "search_clicks_P"), # mandatory.
organic_vars = "newsletter", # marketing activity without media spend
window_start = "2016-01-01",
window_end = "2018-12-31",
adstock = "geometric" # geometric, weibull_cdf or weibull_pdf.
)
print(InputCollect)