WifiConfiguration: Make NetworkSelectionStatus public

Expose a public constructor for |NetworkSelectionStatus| class and add a
setter in WifiConfiguration to set the |NetworkSelectionStatus| object.
Needed for config store persistence of this object.

BUG: 29273147
Change-Id: I9d9036928137760c4832567dd2b9d0fabc874940
TEST: Unit tests
(cherry picked from commit 6a89ee2d908add0d418995420b2d5eaebd90882f)
1 file changed