Adding a test result multiple times

[lordpomeroy]

Issue:
The same test can be assigned a result multiple times. This leads to multiple events in the "Verlauf" Tab for this patient.

Desired solution:
Normal behavior should be to only add a test result once. The search should not show test IDs for tests that already have a test result. The test result should only show once as an event in the status flow.

Nevertheless it must be necessary to update a test result in case of user error. In this case the event must be logged to allow an audit trail. This should only be done once the status and audit are done with a concept to avoid duplicate work.