Improve responsiveness of toggling wifi and refactor user restriction logic.

Moved logic for handling wifi state changes into correct listener
method. Changed logic for handling isUiRestricted. This should
streamline toggling flow for WiFi both when Wifi Scanning is on and off,
and in guest mode.

Bug: 36724409
Bug: 36711085
Bug: 36398321

Test: make, test cases in tracking bug
Change-Id: I69fe07369db192c94f81dd678087ac4e8c35197b