[Regression] Tree tables no longer support horizontal scroll

[kenzieschmoll]

Tree tables used to support horizontal scrolling once the data exceeded the bounds of the column, and now tree tables do not.

This is crucial, as trees can be very deep, and we need to be able to see all the data.
@jacob314 could this have been caused by some part of the table refactor?

[jacob314]

It could be although it would be a bit surprising. I would suggest bisecting the build to verify, Likely some CSS for the allowed width of the tables changed.

[kenzieschmoll]

Bisection confirms #873 is the culprit.