Review fixes for jsf-myfaces-1.2:javaagent (open-telemetry#17481)

Co-authored-by: otelbot <197425009+otelbot@users.noreply.github.com>

Author: otelbot[bot]

instrumentation/jsf/jsf-myfaces-1.2/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/myfaces/MyFacesErrorCauseExtractor.java

@@ -8,7 +8,7 @@
 import io.opentelemetry.javaagent.instrumentation.jsf.javax.JsfErrorCauseExtractor;
 import javax.el.ELException;
 
-public class MyFacesErrorCauseExtractor extends JsfErrorCauseExtractor {
+final class MyFacesErrorCauseExtractor extends JsfErrorCauseExtractor {
 
   @Override
   public Throwable extract(Throwable error) {

instrumentation/jsf/jsf-myfaces-1.2/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/myfaces/MyFacesInstrumentationModule.java

@@ -24,8 +24,9 @@ public MyFacesInstrumentationModule() {
 
   @Override
   public ElementMatcher.Junction<ClassLoader> classLoaderMatcher() {
-    // javax.faces was renamed to jakarta.faces in JSF 3.0
-    return hasClassesNamed("javax.faces.context.FacesContext");
+    return hasClassesNamed(
+        // removed in 3.0
+        "javax.faces.context.FacesContext");
   }
 
   @Override

instrumentation/jsf/jsf-myfaces-1.2/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/myfaces/MyFacesSingletons.java

@@ -10,7 +10,7 @@
 import io.opentelemetry.javaagent.bootstrap.internal.ExperimentalConfig;
 import io.opentelemetry.javaagent.instrumentation.jsf.javax.JsfRequest;
 
-public class MyFacesSingletons {
+final class MyFacesSingletons {
   private static final String INSTRUMENTATION_NAME = "io.opentelemetry.jsf-myfaces-1.2";
 
   private static final Instrumenter<JsfRequest, Void> instrumenter;