WifiEnterpriseConfig - Stop depending on constants from android.security.Credentials

WifiEnterpriseConfig depends on @hide constants from
android.security.Credentials. Since we can no longer
reference @hide APIs once we compile against
@SystemApi stubs, copy the constants into the Wifi
module.

Bug: 145409537
Test: compiles
Change-Id: I0b57d622f4e0788a3fd45109ab2f12976b706087
1 file changed