Fix: Opening inventory menus in spectator mode (#4407)

Revert to spectator_viewer instead of the native Bedrock spectator menu. While it looks uglier - e.g. it's showing health/hunger bars; it allows opening menus. It'll also be needed for entity spectating, since clicking on things isnt possible in bedrocks spectator mode

core/src/main/java/org/geysermc/geyser/util/EntityUtils.java

@@ -270,7 +270,7 @@ public final class EntityUtils {
         return switch (gamemode) {
             case CREATIVE -> GameType.CREATIVE;
             case ADVENTURE -> GameType.ADVENTURE;
-            case SPECTATOR -> GameType.SPECTATOR;
+            case SPECTATOR -> GameType.SURVIVAL_VIEWER;
             default -> GameType.SURVIVAL;
         };
     }