Change IconDelegate::paintIcons to only execute when iconWidth > 0

[mick-lue]

Bug

When too many Content Icons are supposed to render in too little space in the mod table, the code tries to create a pixmap with dimensions 0x0 resulting in a null icon and generating warning messages in the log.

How to reproduce

• create a mod (or separator with many mods below it) which include many different file content categories
• 11 different content categories triggered the warning messages for me on default MO2 resolution with 1440p monitor
• alternatively resize the Content row to make it very small
• You might need to scroll to a "new" entry to trigger this code

Fix

Calculate the iconWidth first and then decide if we want to draw icons.

Side effects?

I didn't encounter any unusual behavior and have been using this for a week now.
Content categories still get shown as usual when hovering over the content row of a modlist entry where this code skipped the icon painting.
It also looks the same whether or not null icons get "drawn".
Anything else that needs to be tested?

Edit: I said "category" but I meant "content"

Example: