Housing Market Tracker: switch to is_outlier, add 2025 sales

[wrridgeway]

Let's add 2025 data to the HMT, and switch what currently uses sv_outlier to is_outlier!

[wrridgeway]

@ccao-jardine as of #977, is this still necessary?

[kyrasturgill]

I don't think any action is necessary from @wrridgeway at this point. I was able to update a draft of the Market Tracker without anything breaking thanks to inclusion of sale_filter_is_outlier alias. Unless we want to go ahead and adjust vw_market_tracker to use is_outlier at this moment.