Fix the ghost unit turning green when hovering an ennemy structure (#2175)

## Description:

Fix the ghost unit turning green when hovering an ennemy structure

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

DISCORD_USERNAME

src/client/graphics/layers/StructureIconsLayer.ts

@@ -277,7 +277,9 @@ export class StructureIconsLayer implements Layer {
 
         if (unit.canUpgrade) {
           this.potentialUpgrade = this.renders.find(
-            (r) => r.unit.id() === unit.canUpgrade,
+            (r) =>
+              r.unit.id() === unit.canUpgrade &&
+              r.unit.owner().id() === this.game.myPlayer()?.id(),
           );
           if (this.potentialUpgrade) {
             this.potentialUpgrade.iconContainer.filters = [