[WifiSettings2] Remove redundant save() call for new configs

Removing call to WifiManager#save() when configuring a new network
through tapping it in the wifi picker. Since WifiManager#connect()
already saves the passed in WifiConfiguration, the call to
WifiManager#save() is redundant.

Bug: 149579116
Test: build, manual verification by connecting to a new secure network
Change-Id: I9242e7fd7e9a459e8221b6bb491ab67833970e87