Fix calculation of durationInForeground when autoCaptureSessions is false

[fractalwrench]

Goal

If autoCaptureSessions is set to false, the app.durationInForeground value always equals 0 in reports.

Additionally, if the app is put into the background and then brought back into the foreground within a 30 second threshold, the durationInForeground value is not reset, and can be erroneously large.

This changeset fixes these two issues.

Design

Please see the design doc for a detailed overview.

Tests

Added a mazerunner scenario to verify that durationInForeground is > 0 when autoCaptureSessions is false. Additionally, manual testing checked the following scenarios, for both potential values of autoCaptureSessions:

• Handled/Unhandled exceptions have non-zero value for durationInForeground
• Putting the activity in the background (by clicking the home button then recent tasks button) immediately resets the durationInForeground field

[Pezzah]

Can there be a test for the application sending an error while it is not in the foreground, and check that durationInForeground is set to zero

[fractalwrench]

thanks @Pezzah - I've added a mazerunner scenario that verifies the inForeground and durationInForeground values when the app exits the foreground.