Add WIFI_SCANNING_SETTINGS action to Settings

- Export the interface for System UI to launch Wi-Fi Scanning Settings.

Bug: 202323013
Test: manual test by adb to launch Wi-Fi scanning settings below
adb shell am start -a android.settings.WIFI_SCANNING_SETTINGS

Change-Id: I893d3cea40d1f3ed4a962009416f54c99a91e11f
(cherry picked from commit 9e6966d1)