fix: Fix restart function

restart 시 restart 전 단계의 formation으로 시작하는 문제 해결
INVADERS-74

Author: BaeGayeon

src/screen/GameScreen.java

@@ -37,6 +37,9 @@ public class GameScreen extends Screen {
 	private static final int SCREEN_CHANGE_INTERVAL = 1500;
 	/** Height of the interface separation line. */
 	private static final int SEPARATION_LINE_HEIGHT = 40;
+	/** Difficulty settings for level 1. */
+	private static final GameSettings RESTART_SETTING =
+			new GameSettings(5, 4, 60, 2000);
 
 	/** Current game difficulty settings. */
 	private GameSettings gameSettings;
@@ -72,7 +75,7 @@ public class GameScreen extends Screen {
 	private boolean bonusLife;
 	/** Pause Screen */
 	private Screen pausescreen;
-
+	/** Title Screen */
 	private Screen titlescreen;
 	/** Check if game is pause */
 	private boolean isPause;
@@ -310,6 +313,9 @@ else if (this.returnCode == 7) {
 						this.level = 1;
 						this.score = 0;
 						this.lives = 3;
+						this.bulletsShot = 0;
+						this.shipsDestroyed = 0;
+						this.gameSettings = RESTART_SETTING;
 						initialize();
 						this.logger.info("Restart");
 						this.isPause = false;