fix(docker): disable use_tunnel in RemoteBrowser

since our monitoring node in docker backend isn't a real
instance, we don't need the tunneling, and we can run
it locally as is

some nemesis code it decorated with functions
that generate grafana screenshots, hence we need
this fixed

sdcm/utils/remotewebbrowser.py

@@ -64,7 +64,8 @@ def web_driver_docker_client(self) -> Optional[DockerClient]:
 class RemoteBrowser:
     def __init__(self, node, use_tunnel=True):
         self.node = node
-        self.use_tunnel = bool(self.node.ssh_login_info and use_tunnel)
+        backend = self.node.parent_cluster.params.get("cluster_backend")
+        self.use_tunnel = bool(self.node.ssh_login_info and use_tunnel and backend not in ('docker',))
 
     @cached_property
     def browser(self):