[Bug] Alert to case merge is broken in v4.0.1

[KaanSK]

Alert to case merge functionality is broken in v4.0.1

Request Type

Bug

Work Environment

Question	Answer
OS version (server)	Debian
OS version (client)	Windows, Linux
TheHive version / git hash	4.0.1
Package Type	DEB, Docker
Browser type & version	All browsers

Problem Description

When an alert is merged into any case, tags and observables are stored in the case but no reference to alert that has been merged can be found.

After merging an alert to case:

• Alert Status: New
• Case Alerts: No indicator (no alerts can be seen)
• Case Description: "Merged with alert #XXXYYY New Alert"
• Case observables: Observables coming from alert

Steps to Reproduce

1. Create an empty case
   

2. Create an alert with observables
   

3. Merge alert to case created in step 1
   

4. Checking the alert after merge
   

5. Checking the case after merge
   

Complementary information

After merge there should be 'alerts' tab on case. Additionally the alert should have 'imported' status on it.