Only one receiver displayed when investigation with multiple parts from different BPNs was created

[rogocof]

Links

• relates to [Concept] Handle messages sent to multiple BPNs in the notification message history #774
• relates to Concept: Notification Model #831
• relates to [Concept] Quality notifications to multiple BPNs #849

Description

An Investigation which was started for multiple parts from different suppliers only shows one receiver in the UI and the API response payload.

Current behaviour

Only one receiver is named under "Send To BPN" in the UI. (See red mark on screenshot)

In database there are one entry for a new investigation and two entries for investigation_notifications created for this case. From database perspective the logic works fine. However the filter API for investigation returns an InvestigationResponse object which has a "sendTo" field with type String. The value for this field is mapped in the InvestegationResponseMapper class by taking the first notification and taking its "sendTo" value:

Expected behavior

A list of string is returned for the sendTo field is returned from the API and visualized in the UI because an Investigation can have multiple receivers.

Steps to reproduce the Bug

1. Start a new investigation with 2 parts from different suppliers.
   
   
2. Open the queued investigation list. You see one investigation.
   
3. Click on the investigation to open the detail view:
   

[mkanal]

links to #774

[ds-crehm]

This was discussed in #774 and #849
The result of the dicsussion and the created concept is the following: When creating a notification with parts from multiple different suppliers, a separate notification will be created for each supplier. In a single notification, there will be no possibility to have multiple "sendTo" receivers anymore.
That will solve this issue and it will be implemented with the tickets #899 (backend) and #900 (frontend)