docs: fix tip about opening the Hubble server port on all nodes
docs: fix tip about opening the Hubble server port on all nodes

The documentation page about setting up Hubble observability wrongly
states that TCP port 4245 needs to be open on all nodes running Cilium
to allow Hubble Relay to operate correctly. This is incorrect. Port 4245
is actually the default port used by Hubble Relay, which is a regular
deployment and doesn't require any particular action from the user.

However, Hubble server uses port 4244 by default and, given that it is
embedded in the Cilium agent and uses a host port, it requires it to be
open on all nodes to allow Hubble Relay to connect to each Hubble server
instance.

Signed-off-by: Robin Hahling <042b6757f29293f4affc22596084b908e3917891@gw-computing.net>

cilium/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium