EKAN Featured Topics view with empty icon code looks broken

Problem/Motivation

Topic with empty icon code looks ugly in EKAN Featured Topics view

Steps to reproduce

Add a topic without an icon code and link a dataset with this topic
check frontpage and see that there is &#x; displayed instead of an icon

Proposed resolution

Display no icon if topic icon code field is empty

Remaining tasks

create patch

User interface changes

n. a.

API changes

n. a.

Data model changes

n. a.