This does the following changes:
* Show info "warnings" in modifier too. Previously those were skipped. The
different behavior of info/warning/error messages causes confusion.
* Add a new `Warnings` panel that only shows when there are warnings. In its
title, it shows how many warnings there are.
* In the panel, warnings are sorted by severity and alphabetically.
Pull Request: https://projects.blender.org/blender/blender/pulls/128395