fix(jakarta): webconsole needs http-whiteboard for Felix WebConsole 5.0.18 servlet registration

Felix WebConsole 5.0.18 registers its OsgiManager servlet via OSGi HTTP
Whiteboard (jakarta.servlet.Servlet service) instead of the legacy HttpService.
The pax-web-extender-whiteboard bundle is required to process this registration,
so the webconsole feature now depends on http-whiteboard instead of http.

Also fix HttpTest.testIncorrectProxyUrlFails to handle the IllegalArgumentException
thrown by the new validateUrl() in ProxyServiceImpl for URLs not starting with '/'.

Author: jbonofre

assemblies/features/standard/src/main/feature/feature.xml

@@ -952,7 +952,7 @@ uninstall = admin
     </feature>
 
     <feature name="webconsole" description="Base support of the Karaf WebConsole" version="${project.version}">
-        <feature>http</feature>
+        <feature>http-whiteboard</feature>
         <feature>jaas-boot</feature>
         <config name="org.apache.karaf.webconsole">
 ################################################################################

itests/test/src/test/java/org/apache/karaf/itests/HttpTest.java

@@ -74,7 +74,11 @@ public void testProxy() throws Exception {
 
     @Test
     public void testIncorrectProxyUrlFails() throws Exception {
-        executeCommand("http:proxy-add no-slash-prefix http://karaf.apache.org");
+        try {
+            executeCommand("http:proxy-add no-slash-prefix http://karaf.apache.org");
+        } catch (RuntimeException e) {
+            // expected - validateUrl rejects URLs not starting with '/'
+        }
         String output = executeCommand("http:proxy-list");
         assertContainsNot("no-slash-prefix", output);
     }