Name already in use

This removes the `--net=host` argument passed to the devcontainer.
Originally introduced for X11 forwarding, devcontainer already passes
`--network host` argument doing the same
[thing](https://stackoverflow.com/q/50644889/8429267)?
Check the build logs
```
Start: Run: docker run --sig-proxy=false -a STDOUT -a STDERR --mount type=bind,src=/var/lib/docker/codespacemount/workspace,dst=/workspaces --mount source=/root/.codespaces/shared,target=/workspaces/.codespaces/shared,type=bind --mount source=/var/lib/docker/codespacemount/.persistedshare,target=/workspaces/.codespaces/.persistedshare,type=bind --mount source=/.codespaces/agent/mount,target=/.codespaces/bin,type=bind --mount source=/mnt/containerTmp,target=/tmp,type=bind --mount type=bind,src=/.codespaces/agent/mount/cache,dst=/vscode -l Type=codespaces -e CODESPACES=true -e ContainerVersion=12 -e RepositoryName=next.js --label ContainerVersion=12 --hostname codespaces-9b31fb --add-host codespaces-9b31fb:127.0.0.1 --cap-add sys_nice --network host --cap-add SYS_PTRACE --security-opt seccomp=unconfined --entrypoint /bin/sh vsc-next.js-e4966344b9ebb252cd82cad8e4b143f1 -c echo Container started
```

[Refer](#43138 (comment))
for original issue with the current configuration. Closes #43451

P.S. Why do we have X11 support in devcontainers in the first place? Its
not something *most* people will use, especially if it comes with the
cost of codespaces not working. Need someone to verify if X11 forwarding
still works with this configuration as it probably should.