gtkiconhelper: also apply icon effects when the source is a cairo surface. Fixes #1542

gtk_css_icon_effect_apply() was only called on all icon types that were converted
to cairo surfaces but not on cairo surfaces themselves.

This was for example visible when moving a GtkImage from GdkPixbuf to cairo_surface_t
and gtk_widget_set_sensitive() on the image no longer having any effect.

To fix this copy the surface and apply the effect in case there is an effect active.
Otherwise just use the surface as is.
3 jobs for surface-icon-effects in 62 minutes and 58 seconds (queued for 1 second)
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passed #178670
build

00:08:12

passed #175357
win32 allowed to fail manual
msys2-mingw32

00:54:45

passed #175356
build

00:07:48