Remove "New private tab" action and widget

Summary

Summarize the bug encountered concisely. After a long press on the icon, there is a "New private tab" button that has a lot of issues surrounding it (often breaking the app) and I don't think that we need it. For instance if you tap on it when already connected to tor, you can get the screen in the second screenshot. If you then try to search you get the 3rd screenshot. It also has firefox branding (the eye mask).

Relevant logs and/or screenshots