Add system property to skip packet compression threshold validation

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftCompressDecoder.java

@@ -39,6 +39,7 @@ public class MinecraftCompressDecoder extends MessageToMessageDecoder<ByteBuf> {
   private static final int UNCOMPRESSED_CAP =
       Boolean.getBoolean("velocity.increased-compression-cap")
           ? HARD_MAXIMUM_UNCOMPRESSED_SIZE : VANILLA_MAXIMUM_UNCOMPRESSED_SIZE;
+  private static final boolean SKIP_COMPRESSION_VALIDATION = Boolean.getBoolean("velocity.skip-uncompressed-packet-size-validation");
 
   private int threshold;
   private final VelocityCompressor compressor;
@@ -52,9 +53,11 @@ public class MinecraftCompressDecoder extends MessageToMessageDecoder<ByteBuf> {
   protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
     int claimedUncompressedSize = ProtocolUtils.readVarInt(in);
     if (claimedUncompressedSize == 0) {
+      if (!SKIP_COMPRESSION_VALIDATION) {
         int actualUncompressedSize = in.readableBytes();
         checkFrame(actualUncompressedSize < threshold, "Actual uncompressed size %s is greater than"
             + " threshold %s", actualUncompressedSize, threshold);
+      }
       // This message is not compressed.
       out.add(in.retain());
       return;