[Bug] Pulsar's containers fail to start in k8s with readOnlyRootFilesystem pod/container security context

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar.

### Version

any, for example 3.0.2

### Minimal reproduce step

```
❯ docker run --user 10000:10001 -e advertisedAddress=foobar --rm --read-only apachepulsar/pulsar:3.0.2 sh \
-c "bin/apply-config-from-env.py \
conf/standalone.conf && \
bin/pulsar standalone"
[conf/standalone.conf] Applying config advertisedAddress = foobar
Traceback (most recent call last):
File "/pulsar/bin/apply-config-from-env.py", line 104, in
f = open(conf_filename, 'w')
OSError: [Errno 30] Read-only file system: 'conf/standalone.conf'
```

### What did you expect to see?

I should be possible to run Pulsar container with read only root filesystem.

### What did you see instead?

`OSError: [Errno 30] Read-only file system` error

### Anything else?

_No response_

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

Start with bin/apply-config-from-env.py and the conf/standalone.conf step in the reproduction, then trace how bin/pulsar starts in the apachepulsar/pulsar container. Reproduce with Docker's read-only root filesystem and the Kubernetes security context; done means the container starts without the read-only filesystem error.

Written by the indexing model from the issue text.