Buttons on Symptom-Screens scroll with the screen (EXPOSUREAPP-4595) #2178

* mounted navigation button to bottom on symptom screen

* mounted navigation button on symptom calender screen to bottom

* aligned button margins

* simplified margins

* removed unused code

* fixed instrumentation tests

Co-authored-by: harambasicluka <64483219+harambasicluka@users.noreply.github.com>
Co-authored-by: Ralf Gehrer <ralfgehrer@users.noreply.github.com>