Fix NPE in 1.16 TranslatableRewriter

Closes ViaVersion/ViaVersion#2655

common/src/main/java/com/viaversion/viabackwards/protocol/protocol1_15_2to1_16/chat/TranslatableRewriter1_16.java

@@ -54,7 +54,8 @@ public class TranslatableRewriter1_16 extends TranslatableRewriter {
     @Override
     public void processText(JsonElement value) {
         super.processText(value);
-        if (!value.isJsonObject()) return;
+
+        if (value == null || !value.isJsonObject()) return;
 
         // c o l o r s
         JsonObject object = value.getAsJsonObject();