VCN: Refactor getPacketLossRatePercentage to return an object

Refactor getPacketLossRatePercentage to return an object instead of
an integer. This is for extending the Packet Loss Detector's ability
to handle inbound sequence number leap

This patch does not include any behavior changes

Bug: 332598276
Test: atest FrameworksVcnTests && atest CtsVcnTestCases
Change-Id: Ied42e581fb331ab0603225865236779f50cc4881
2 files changed