Add Service tests for Profiling

- Add tests for ProfilingService covering up to but not including starting the trace (starting trace cannot be done from this context and will be covered in subsequent ProifilingManager tsts)
- Rework rate limiter to not be static for better testability (this will also help with a cleaner persisting impl)

Test: run new tests, presubmit, manual test
Bug: 293957254
Change-Id: If735259c3c1cc85752917e0e8606e94c63447286