Remove devcontainer network host argument (#44157)

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.

.devcontainer/devcontainer.json

@@ -32,8 +32,6 @@
     // Github latest can't be installed due to GPG issues: https://github.com/cli/cli/discussions/6222
     // "github-cli": "latest",
   },
-  // This is needed for forwarding X11: https://github.com/microsoft/vscode-remote-release/issues/3841
-  "runArgs": ["--net=host"],
   "remoteEnv": {
     "DISPLAY": ":0"
   }