Fix "Login to play!" when session has 2 players.

Shogi.UI/Pages/Play/GameBoard/GameBoardPresentation.razor

@@ -98,7 +98,10 @@
 			</Authorized>
 			<NotAuthorized>
 				<aside class="login-to-play PrimaryTheme ThemeVariant--Contrast" style="grid-area: player-side-board">
+					@if (Perspective == WhichPlayer.Player2 && string.IsNullOrEmpty(Session.Player2))
+					{
 						<p><a href="login">Log in</a> to play!</p>
+					}
 				</aside>
 			</NotAuthorized>
 		</AuthorizeView>