Bash option 'set -e' is ignored

# Bug report

You usually use [set -e](https://gist.github.com/vncsna/64825d5609c146e80de8b1fd623011ca) to exit a script on error. `cloud-init status` should be `error` now. But `cloud-init` continues and ends up with status `done`.

`cloud-init status --long`

```
status: done
extended_status: done
boot_status_code: enabled-by-generator
last_update: Thu, 01 Jan 1970 00:01:48 +0000
detail: DataSourceHetzner
errors: []
recoverable_errors: {}
```

## Steps to reproduce the problem

```yaml
#cloud-config
write_files:
- owner: root:root
path: /root/.cloud-init/some-script.sh
content: |
#!/bin/bash

set -e

a command that will fail

runcmd:
- /bin/bash /root/.cloud-init/some-script.sh
```

## Environment details
- Cloud-init version: `24.3.1-0ubuntu0~24.04.2`
- Operating System Distribution: `Ubuntu 24.04.1 LTS`
- Cloud provider, platform or installer type: `hcloud`

## cloud-init logs

```
/root/.cloud-init/some-script.sh: line 5: a: command not found
```