Clean up XL Wifi setup and fix misc problems.

- Introduce screen state, which suppress inconsistent
  UI shown in 3378805.
- Introduce initSecurityFields(), which will reduce hook
  inside WifiConfigController#showSecurityfields()
- fix layout for eap-not-supported case with "add network"
  flow.

Bug: 3378805
Bug: 3403168
Change-Id: I52895570809095d9baceac5f84665572188ecefd
5 files changed