Logging in WebComponentExporterUtils should be using WARN and not TRACE

[Artur-]

Description of the bug / feature

Say that you create this

public static class HelloWorldExporter extends WebComponentExporter<HelloWorld> {

        protected HelloWorldExporter() {
            super("hello-world");
        }

        @Override
        protected void configureInstance(WebComponent<HelloWorld> webComponent, HelloWorld component) {

        }

    }

The intent is pretty clear: you want HelloWorld to be exported as <hello-world>
It does not work and no warnings are logged. It is unclear what to do next.

WebComponentExportedUtils.isEligible notices the problem and logs, with TRACE level

                    "Class {} has no public no-argument constructor, and won't be instantiated as a '{}' by default",

This and the other errors in isEligible should be at least WARN so that you see what is wrong.

[denis-anisimov]

Even though it looks like an enhancement I set it as a bug because you won't be able to detect any problems if you don't use TRACE level which is quite rare.

I thought we have checks for protected CTOR specifically for the exporter for some other reasons which I don't recall already.