Fix set_beacon packet handling in 1.19->1.18.2 (#1241)

Author: riku6460

common/src/main/java/com/viaversion/viabackwards/protocol/v1_19to1_18_2/rewriter/BlockItemPacketRewriter1_19.java

@@ -159,15 +159,15 @@ public void register() {
 
         protocol.registerServerbound(ServerboundPackets1_17.SET_BEACON, wrapper -> {
             final int primaryEffect = wrapper.read(Types.VAR_INT);
-            if (primaryEffect != -1) {
+            if (primaryEffect > 0) {
                 wrapper.write(Types.BOOLEAN, true);
                 wrapper.write(Types.VAR_INT, primaryEffect);
             } else {
                 wrapper.write(Types.BOOLEAN, false);
             }
 
             final int secondaryEffect = wrapper.read(Types.VAR_INT);
-            if (secondaryEffect != -1) {
+            if (secondaryEffect > 0) {
                 wrapper.write(Types.BOOLEAN, true);
                 wrapper.write(Types.VAR_INT, secondaryEffect);
             } else {