upgrades not counting towards building discount bugfix (#1361)

## Description:

Upgrading units was not being counted towards building discounts

## 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
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

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

evan

src/core/game/PlayerImpl.ts

@@ -828,6 +828,7 @@ export class PlayerImpl implements Player {
     const cost = this.mg.unitInfo(unit.type()).cost(this);
     this.removeGold(cost);
     unit.increaseLevel();
+    this.recordUnitConstructed(unit.type());
   }
 
   public buildableUnits(tile: TileRef): BuildableUnit[] {