Modify threshold parameters for signal strength reporting criteria

The following two points are added.
- Modify threshold parameter to be able to specify signal measurement
type.
- Add test verification of RSRQ and RSSNR threshold.

Test: manual - Checked that signal measurement type can set to
threshold parameter.
Test: auto - SignalStrengthTest and SignalThresholdInfoTest are passed.
Bug: 133400544

Change-Id: I53dafb17dc9fa4d381dc8876f8420275096449c3
Merged-In: I53dafb17dc9fa4d381dc8876f8420275096449c3