Use resumegamemode to track menu animation

This fixes a bug where the player could bring up the map on the very
first frame of a gamemode(game) animation. This is because the menu
animation checked graphics.menuoffset, but graphics.menuoffset wouldn't
have changed at that point because it only set graphics.resumegamemode.

Instead, just check for graphics.resumegamemode directly. We also need
to assign it to false whenever the map is closed so the player won't be
prevented from using the map screen again.

desktop_version/src/Game.cpp

@@ -6863,9 +6863,7 @@ void Game::unlockAchievement(const char *name) {
 
 void Game::mapmenuchange(const int newgamestate, const bool user_initiated)
 {
-    if (user_initiated
-    && graphics.menuoffset > 0
-    && graphics.menuoffset < 240)
+    if (user_initiated && graphics.resumegamemode)
     {
         return;
     }

desktop_version/src/RenderFixed.cpp

@@ -213,6 +213,7 @@ void maprenderfixed(void)
                 //go back to gamemode!
                 game.mapheld = true;
                 game.gamestate = GAMEMODE;
+                graphics.resumegamemode = false;
             }
         }
         else