Add an intent for launching mobile network list

In various cases when a user has rebooted their device to enable DSDS
mode, the eSIM manager app needs to be able to post a notification that
on tapping will lead the user to the list of configured SIMs (mobile
networks) so that they can they manage things like which one is the
default for calls, SMS, and data.

Bug: 129281152
Test: 'adb shell am start -a android.settings.MOBILE_NETWORK_LIST'
should launch the list of mobile networks available on the device

Change-Id: Ie94d937c803fb5ade09084f2c994cfff888d8aa7