Use realtime to maintain 24-hour fgs tracking.

All FGS tracking currently is in the uptime base, however, the 24-hour
time limit reset window for time-limited fgs types is based in realtime.
Maintain a separate first-start-time bit in the tracking info which will
be used to determine if the time limits should be reset.

Bug: 330399444
Test: atest CtsFgsTimeoutTestCases
Change-Id: Iae008c74d598f4dce4cef8ae1a7cc7af7f2f63be