refactor: use supported syntax in testcases

Author: zimeg

slack-api-model/src/test/java/test_locally/api/model/block/BlocksTest.java

@@ -94,7 +94,7 @@ public void testContextActions() {
                                     .style("danger")
                                 )
                             )
-                            .visibleToUserIds(List.of("USLACKBOT", "U0123456789"))
+                            .visibleToUserIds(Arrays.asList("USLACKBOT", "U0123456789"))
                             )
                     ))
                 ), is(notNullValue()));