Prevent brief flash of "Error" in hotspot status text

When toggling the master preference to turn on wifi hotspot, it briefly
changes the status text to "Error" because we have a catch-all in a
function monitoring wifi state changes for unexpected status codes, and
we weren't expecting to see the status of WIFI_AP_STATE_ENABLING before
the status of WIFI_AP_STATE_ENABLED.

Bug: 64811203
Test: make RunSettingsRoboTests
Change-Id: Ifba7abadbfba9ce93cc524b17232c65570f0f428