Add Telecom command for setting connectionservice filter

For testing we need the emergency call to go through the CTS
ConnectionService. This is achieved by passing in a package
name filter for testing, which restricts which ConnectionServices
are available for emergency calling.

For safety this filter will be bypassed if the user calls an
actual emergency number (instead of a test number).

Bug: 138741228
Test: atest CtsTelecomTestCases
Change-Id: I656533e4a36a7bba48625bf6f763731991695aed