Enable the prefer-destructuring eslint rule (#1858)

## Description:

Enable the `prefer-destructuring` eslint rule.

## 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

src/core/execution/FakeHumanExecution.ts

@@ -67,7 +67,7 @@ export class FakeHumanExecution implements Execution {
   }
 
   private updateRelationsFromEmbargos() {
-    const player = this.player;
+    const { player } = this;
     if (player === null) return;
     const others = this.mg.players().filter((p) => p.id() !== player.id());
 
@@ -90,7 +90,7 @@ export class FakeHumanExecution implements Execution {
   }
 
   private handleEmbargoesToHostileNations() {
-    const player = this.player;
+    const { player } = this;
     if (player === null) return;
     const others = this.mg.players().filter((p) => p.id() !== player.id());
 
@@ -248,7 +248,7 @@ export class FakeHumanExecution implements Execution {
     if (other.isTraitor()) {
       return false;
     }
-    const difficulty = this.mg.config().gameConfig().difficulty;
+    const { difficulty } = this.mg.config().gameConfig();
     if (
       difficulty === Difficulty.Hard ||
       difficulty === Difficulty.Impossible
@@ -491,7 +491,7 @@ export class FakeHumanExecution implements Execution {
   private structureSpawnTileValue(type: UnitType): (tile: TileRef) => number {
     if (this.player === null) throw new Error("not initialized");
     const borderTiles = this.player.borderTiles();
-    const mg = this.mg;
+    const { mg } = this;
     const otherUnits = this.player.units(type);
     // Prefer spacing structures out of atom bomb range
     const borderSpacing = this.mg.config().nukeMagnitudes(UnitType.AtomBomb).outer;