wifi: Fix 3(!) different crashes with the Saved Networks dialog

See the individual commits for all the crashes this fixes. This was not trivial since the toasts dismissal behavior makes everything happen out of sync.

Fixes #2793 (closed)

I realize this is another big MR, but I could not think of an easier way to fix all these crashes. As an added benefit, there is also a lot of clean up. However, we do lose almost 100 lines, so not too bad :)