[rootless] bridge network degrading ending in failure to expose port

### Description

After some time testing:

```
nerdctl run -d --name bar -p 5003:80 nginx
6c1fa26eba42ff417d193acd3b7097ba33a3764a8a52efad49c4a1a99c8c4435

curl localhost:5003
curl: (56) Recv failure: Connection reset by peer
```

This is specific to that port - that has been used (past tense) by other containers (not specific to `5003` - just specific to whichever port has been used heavily).

It looks like after these containers got destroyed, something in cni (?) does not completely release the port (maybe in iptables?).

This is tricky to reproduce - I usually trigger this with repeatedly running test suite.

- cni 1.5.1
- containerd v2rc5
- nerdctl main