Remove addressed TODO

Author: timgrein

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/expression/function/fulltext/DecayTests.java

@@ -29,7 +29,6 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.startsWith;
 
-// TODO: check null args in VerifierTests
 public class DecayTests extends AbstractScalarFunctionTestCase {
 
     public DecayTests(@Name("TestCase") Supplier<TestCaseSupplier.TestCase> testCaseSupplier) {