Text shown on game portal signs should be vertically centered

[haykam821]

Right now, text is shown on the first and second lines of game portal signs:

plasmid/src/main/java/xyz/nucleoid/plasmid/mixin/game/portal/SignBlockEntityMixin.java

Lines 65 to 75 in 4502294

	if (line == 0) {
	var name = display.get(GamePortalDisplay.NAME);
	if (name != null) {
	return name;
	}
	} else if (line == 1) {
	var playerCount = display.get(GamePortalDisplay.PLAYER_COUNT);
	if (playerCount != null) {
	return Text.translatable("text.plasmid.game.portal.player_count", playerCount);
	}
	}

Since signs support four lines in total, the text should be shown on the second and third lines instead.