Add LISTEN_ALWAYS_REPORTED_SIGNAL_STRENGTH into Shell permission

> Is the minimally scoped permission that needs to be added?
This is a minimal permission for always listening to signal strength.

> What options did you explore that did not need this permission?
CTS is required by API council; Telephony CTS is using shell to have
system permission. I don't see other options.

Integrate the callback of LISTEN_ALWAYS_REPORTED_SIGNAL_STRENGTH

Test: CTS; https://paste.googleplex.com/5811446241820672
Bug: 147322848
Change-Id: Id5afd261a7f00c25e3af3558f30fb92aad42f060