Adjust EW/PT riskresult combination (EXPOSUREAPP-6169) (#2788)

* Refactoring, move extensions closer to their use-case.

* Adjust riskState combination, if either calculation fails, the combined riskstate is also CALCULATION_FAILED and should show the white failure card on the home screen.

* Introduce ptRiskLevelResult.checkInOverlapCount as analog to ewRiskLevelResult.matchedKeyCount for the CombinedEwPtRiskLevelResult to allow the UI show information for "low risk with encounters" situations.

* LINTs

* Adjust unit tests to reflect the risk status combination priority (FAILED>HIGH>LOW).

* Home screen download/calculation progress should include PresenceTracingWarningTask

* LINTs

Co-authored-by: Lukas Lechner <lukas.lechner@sap.com>
Co-authored-by: harambasicluka <64483219+harambasicluka@users.noreply.github.com>