In cases where plugins extend an existing settings category of a plugin
that they depend on anyhow, they do not need to specify the translated
display name and icon for that category.
Some options pages were already not setting the icon, but still the
translated name, which makes even less sense.
Clean up this mess, only setting display name and icon if that is
necessary.
Change-Id: I8bc9d0c51b11d48f1d847337838704d663e70b45
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>
