Remove logo preload when header logo disabled

[e-five256]

Noticed the following in console when Header logo is disabled in the admin settings

The resource /mbin_logo.svg was preloaded using link preload but not used within a few seconds from the window's load event. Please make sure it has an appropriate `as` value and it is preloaded intentionally.

this makes it only preload the asset if it's going to be used

mbin/templates/layout/_header.html.twig

Lines 16 to 17 in 1657a3f

	{% if kbin_header_logo() %}
	<img id="logo" src="{{ asset('mbin_logo.svg') }}" alt="{{ 'homepage'|trans }}" title="{{ 'homepage'|trans}}">