Bump org.eclipse.jetty:jetty-server in /knox-agent

Bumps org.eclipse.jetty:jetty-server from 9.4.51.v20230217 to 9.4.55.v20240627.

---
updated-dependencies:
- dependency-name: org.eclipse.jetty:jetty-server
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

knox-agent/pom.xml

@@ -23,7 +23,7 @@
     <packaging>jar</packaging>
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-        <knox.jetty.version>9.4.51.v20230217</knox.jetty.version>
+        <knox.jetty.version>9.4.55.v20240627</knox.jetty.version>
     </properties>
     <parent>
         <groupId>org.apache.ranger</groupId>