By default, Cilium's tc filters are added add the highest priority,
which makes it impossible to add any tc filters of our own (because the
Cilium eBPF programs don't return to the filter chain).
Two near-future use cases that would benefit from this:
* Network testing could add counting filters to interfaces and observe
e.g. violations of encryption policy.
* The VPN Helm chart could add a filter policy that drops packets on the
"physical" interface before they can leak to the CSP.
a3de1d95d9