Update unit tests for CellInfo Code Cleanup

The initialize() methods were removed from the
CellSignalStrengthXYZ functions, so instead the
unit tests are updated to use the appropriate
constructors rather than a two-step construct-then
initialize pattern.

Bug: 72742517
Test: runtest frameworks-telephony
Change-Id: Ic6e76a2c71b2aab3a25d8ed680e0a099e51145b4