fix: Update wireguard-with-cilium example

[csantanapr]

What does this PR do?

Update the wireguard-with-cilium example

• Use latest EKS 1.27
• Use latest Cilium 1.13.2
• Update validate instructions to check if data from nginx example is going over wireguard tunnel avoid false positive.
• Add delay after cilium helm install for example pods to communicate using encryption, without this delay the pods will communicate over http (ie security group not created) and not use the wireguard tunnel
• Add security group ingress rule for node to node to allow wireguard traffic to flow using udp/51871

There is still some investigation if someone wants to pick up on why the 15s delay is need it. One theory is that cilium is reporting ready to helm (via probes) but is not done being completed setup.

Motivation

• Resolves [bug] wireguard with cillium example doesn't work  #1618

More

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• Yes, I have updated the docs for this feature
• Yes, I ran pre-commit run -a with this PR

For Moderators

• E2E Test successfully complete before merge?

Additional Notes

[csantanapr]

As future reference, the tcpdump on the wireguard tcpdump -A -i cilium_wg0 interface will show the plain decrypted text over http
To see the encrypted traffic with a tcpdump on eth0 listening for udp/51787 tcpdump -A -i eth0 udp 51787

cc @askulkarni2 @aaroniscode