[Bug] Able to merge alert into closed case, even though it is not allowed

[mphbig]

Request Type

Bug

Work Environment

Question	Awnser
OS version (server)	Debian 9
OS version (client)	Windows 10
Virtualized Env.	True
Dedicated RAM	16 GB
vCPU	8
TheHive version / git hash	4.1.2
Package Type	DEB
Database	Cassandra
Index type	Lucene
Attachments storage	Local
Browser type & version	Firefox and Chrome latest

Problem Description

Even when the option "Check this to disallow merging alerts into closed cases" is checked, it is still possible to merge alerts in closed cases using the "Merge Into Case" button.

Steps to Reproduce

1. Get a new alert
2. Merge the alert in a closed case using the "Merge Into Case" button

Possible Solutions

Ensure the "Merge Into Case" button searches on opened cases (rather than all cases) when the "Check this to disallow merging alerts into closed cases" is checked.

[nadouani]

This configuration option has in fact been create to disallow merging alerts in closed cases from the case similarity view in alert preview, but we should also use it in all the locations related to alert merge into cases.