fix(networkpolicy): use UDP/53 for DNS egress instead of named port

[fmlecpac]

Hello,

What this PR does / why we need it:
The current NetworkPolicy template allows DNS egress using the named port dns.
However, not all clusters define a DNS service port with that name. This can cause the policy to block DNS traffic.

This PR replaces the named port with the standard numeric port 53/UDP, ensuring DNS resolution works consistently across clusters that use standard port for DNS service.

Which issue(s) this PR fixes:
N/A

Special notes for your reviewer:
Should we make it configurable? (especially for clusters with a DNS service not on port 53)

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Tests updated
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• If the change is deprecating or removing a configuration option, update the deprecated-config.yaml and deleted-config.yaml files respectively in the tools/deprecated-config-checker directory. Example PR

[CLAassistant]

All committers have signed the CLA.

[fmlecpac]

Added 53/TCP too.

[jkroepke]

LGTM