Added logic for showing notification on risk level change (EXPOSUREAPP-2569) (#1480)

* Added logic for showing notification on risk level change

* Got rid of magic number

* Fixed ktlint issue

* Notification only shows up when risk card goes from red to green

* Showing dialog onResume

* Added static string for preference key and renamed method to better reflect usage

* Whether not weather

* Showing dialog is handled by the VM

* Fixed ktlint error

* Fixed an issue where the dialog would be shown only after navigating back to the home fragment.

* Move decision logic for showing the lowered risk into the viewmodel.

* Make the lowered risk level score event observable.

* Fix wrong init value used for testing.

* Update strings.xml

* Fix test regressions due to static LocalData access.

Co-authored-by: harambasicluka <64483219+harambasicluka@users.noreply.github.com>
Co-authored-by: Matthias Urhahn <matthias.urhahn@sap.com>