Static files with SSL plugin

[kromar777]

Actual behavior (the bug)
Just added SslPlugin 6.0 to the HelloWorldStaticFiles (Javalin 6.0, not tryed another versions) example and start getting Server Error for any request.

[JettyServerThreadPool-25] WARN io.javalin.Javalin - Uncaught exception java.lang.NullPointerException: Cannot invoke "org.eclipse.jetty.server.HttpConnection.getHttpChannel()" because the return value of "org.eclipse.jetty.server.HttpConnection.getCurrentConnection()" is null at io.javalin.jetty.JettyResourceHandler.jettyRequest(JettyResourceHandler.kt:84) at io.javalin.jetty.JettyResourceHandler.access$jettyRequest(JettyResourceHandler.kt:33) at io.javalin.jetty.JettyResourceHandler$nonSkippedHandlers$1.invoke(JettyResourceHandler.kt:87) at io.javalin.jetty.JettyResourceHandler$nonSkippedHandlers$1.invoke(JettyResourceHandler.kt:87) ...

Expected behavior
Get 200 response and static file content

To Reproduce
Add SslPlugin into HelloWorldStaticFiles example and provide some keystore.
`public class HelloWorldStaticFiles {

public static void main(String[] args) {
    SslPlugin sslPlugin = new SslPlugin(conf -> {
        conf.keystoreFromPath("server_keystore.p12", "password");
        conf.securePort = 7071;
        conf.insecure = false;
        conf.sniHostCheck = false;
    });

    Javalin.create(config -> {
        config.registerPlugin(sslPlugin);
        config.staticFiles.add("/public", Location.CLASSPATH);
    }).start();
}

}`

Additional context
Actually I'm fresh new to Javalin and maybe missing something.
But SslPlugin works OK with "normal" handlers like app.post("/service/jsonrpc", this::handleJsonRpcRequest);

[tipsy]

Fixed in #2087