[CI] Functional: Increase Ulimit to 4096

Functional tests started to fail with
"Too many open files" randomly, the default ulimit in
OS is configured to 1024, increasing this to 4096
to avoid these random failures.

Closes-Bug: #2080199
Change-Id: Iff86599678ebdd5189d5b56d11f3373c9b138562
(cherry picked from commit 6970f39a49b83f279b9e0479f7637d03a123a40e)

roles/configure_functional_tests/tasks/main.yaml

@@ -47,6 +47,10 @@
         fi
 
         configure_host_for_func_testing
+        echo "$USER soft nofile 4096" | sudo tee /etc/security/limits.d/99-user.conf
 
     executable: /bin/bash
   environment: "{{ override_env | default({})}}"
+
+- name: Reset ssh connection to pick up limits
+  meta: reset_connection