feat(crypto): harden ECKey validation

chainbase/src/main/java/org/tron/common/utils/LocalWitnesses.java

@@ -86,6 +86,9 @@ private void validate(String privateKey) {
       throw new TronError("private key must be hex string",
           TronError.ErrCode.WITNESS_INIT);
     }
+    if (!ECKey.isValidPrivateKey(ByteArray.fromHexString(privateKey))) {
+      throw new TronError("Invalid ECDSA witness private key", TronError.ErrCode.WITNESS_INIT);
+    }
   }
 
   public void addPrivateKeys(String privateKey) {