[fix][dingo-sdk] Decimal pushdown - fix key prefix encoding issue.

Author: nokiaMS

java/dingo-sdk/src/main/java/io/dingodb/sdk/common/serial/schema/DecimalSchema.java

@@ -288,7 +288,7 @@ public String decodeKeyPrefix(Buf buf) {
         }
 
         //Forward skip codec version field.
-        buf.reverseSkipInt();
+        //buf.reverseSkipInt();
 
         return internalReadDecimal(buf);
     }
@@ -379,10 +379,14 @@ public void encodeKeyPrefix(Buf buf, String data) {
                 buf.ensureRemainder(1);
                 buf.write(NOTNULL);
 
-                internalEncodeKeyV2(buf, data);
+                int size = internalEncodeKeyV2(buf, data);
+                buf.ensureRemainder(4);
+                buf.reverseWriteInt(size);
             }
         } else {
-            internalEncodeKeyV2(buf, data);
+            int size = internalEncodeKeyV2(buf, data);
+            buf.ensureRemainder(4);
+            buf.reverseWriteInt(size);
         }
     }