fix tomcat error valve classes visibility (#16243)

Co-authored-by: Trask Stalnaker <trask.stalnaker@gmail.com>

Author: SylvainJuge

instrumentation/tomcat/tomcat-10.0/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/tomcat/v10_0/ErrorHandlerValve.java

@@ -10,7 +10,8 @@
 import org.apache.catalina.connector.Response;
 import org.apache.catalina.valves.ErrorReportValve;
 
-class ErrorHandlerValve extends ErrorReportValve {
+// public, because it's loaded by reflection
+public class ErrorHandlerValve extends ErrorReportValve {
   @Override
   protected void report(Request request, Response response, Throwable t) {
     if (response.getStatus() < 400 || response.getContentWritten() > 0 || !response.isError()) {

instrumentation/tomcat/tomcat-7.0/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/tomcat/v7_0/ErrorHandlerValve.java

@@ -10,7 +10,8 @@
 import org.apache.catalina.connector.Response;
 import org.apache.catalina.valves.ErrorReportValve;
 
-class ErrorHandlerValve extends ErrorReportValve {
+// public, because it's loaded by reflection
+public class ErrorHandlerValve extends ErrorReportValve {
   @Override
   protected void report(Request request, Response response, Throwable t) {
     if (response.getStatus() < 400 || response.getContentWritten() > 0 || !response.isError()) {