Dropdown menu for case templates doesnt have scroll

[ghost]

Request Type

Bug

Work Environment

Question	Answer
OS version (server)	Ubuntu Server 16.04
OS version (client)	--
TheHive version / git hash	3.0.8
Package Type	Docker
Browser type & version	Mozilla 58.0.x, Chromium 64.0.x.x

Problem Description

Dropdown menu for case templates doesn’t have scroll feature, so if there is more than 20 case templates, you can't select at least one of them (Zooming the page does the trick... utill you have <80 templates).

Steps to Reproduce

1. Make >20 case templates
2. Click "+ New case" to open dropdown menu

Possible Solutions

Put scrollbar on this dropdown element.

Complementary information

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