Remove unnecessary Dependabot exclusion for `log4j:log4j` (#7505)

.github/dependabot.yml

@@ -24,9 +24,6 @@ updates:
       - dependency-name: "org.eclipse.jetty:jetty-maven-plugin"
       - dependency-name: "org.jenkins-ci:winstone"
 
-      # Log4j 1.2.17 is the final 1.x release.
-      - dependency-name: "log4j:log4j"
-
       # Here lies technical debt. Exclusions in this section have been triaged
       # and determined to be temporary. Exclusions should be removed from this
       # section once the remaining action items have been completed.