Check device time (EXPOSUREAPP-2998) (#1985)

* Let the AppConfig validity check use absolute values, to support device time check behavior.

* Add mapping for "disable-device-time-check" to app config.

* Show popup dialog if the device time is invalid.
* Remove extra retrofit cache (use only LocalAppConfigSource.kt)
* Exposure device time check
* Reset user acknowledgement

* LINTs

* Add test menu option to disable device time check via affecting the config mapping.

* Download, but don't submit keys if device time is incorrect.
Abort risk level calculation if time is incorrect.

* Due to multiple properties in ConfigData affecting `isDeviceTimeCorrect`, make it a body property and don't allow overriding via constructor.

* Add unit test for test settings affecting the device config only in tester builds.

* Show notification regarding incorrect time when device is in the background.

* Fix test regressions and add additional test cases for download and risk task abort conditions on incorrect device time.

* Fix merge regressions.

* Add time unit to log statement.

* Fix incorrect time dialog showing in a loop when entering leaving the home screen.

* Remove unused code path for clear().

* Print additional timestamps to help debugging efforts in the future.