Target: Add support for GameObject icon

[Backupiseasy]

• https://www.curseforge.com/wow/addons/tidy-plates-threat-plates/issues/608
  • So when I enable Threat Plates I get no GameObjectIcoon above the nameplate when soft-targeting
  • When I disable Threat Plates I do get the Icon.
  • Is there a option to enable it? searched everywhere, can't seem to find it.
• https://www.curseforge.com/wow/addons/tidy-plates-threat-plates/issues/605
  • The little icon that pops up when you're close to gathering nodes is being hidden by this addon. I've tracked it down to TP and when I turn off TP they show back up. I've reset TP back to it's defaults, and they still won't show unless I have TP off
  • Icon I'm Talking About Shows up when TP is off
  • Missing Icon When TP is turned on
  • I have also tried every option in TP to see what the conflict is coming from. Nothing in the options seems to engage this behavior, but it is the addon as they come back as soon as I disable it.
  • I'm going to close this. For some reason, it's only the one character where I was getting this behavior. My new alt doesn't do this, at all. I can't replicate the behavior.

[Backupiseasy]

So, I finally found out why these icons are not shown (while working on soft-target icons which these are as well). Basically, the node has a nameplate, but no unit which means UnitExists is nil. Because of some other bugs, I filter out these kind of units for nameplates as a lot of stuff is not working when the unit does not exists.

[Backupiseasy]

GameObjectIcons are now shown since version 11.2.0