Traceback observed in logs while using user-data from file

# Bug report
While no data sources are used and user-data is provided by a file, a traceback is observed.

## Steps to reproduce the problem
Following is my user-data file:
```
#cloud-config

preserve_hostname: true

write_files:
- content: Hello cloudinit
path: /var/log/cloudinit-test.log
permissions: '0644'
```

And then I'm doing:
```
cloud-init clean -ls
cloud-init init --local
cloud-init -d modules --mode init --file user-data
cloud-init -d modules --mode config --file user-data
cloud-init -d modules --mode final --file user-data
```

And then in `/var/log/cloud-init.log`
```
...
2024-05-18 11:01:59,412 - util.py[DEBUG]: Failed to write boot finished file /var/lib/cloud/instance/boot-finished
Traceback (most recent call last):
File "/usr/lib/python3.11/site-packages/cloudinit/config/cc_final_message.py", line 109, in handle
util.write_file(boot_fin_fn, contents, ensure_dir_exists=False)
File "/usr/lib/python3.11/site-packages/cloudinit/util.py", line 2308, in write_file
with open(filename, omode) as fh:
^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '/var/lib/cloud/instance/boot-finished'
2024-05-18 11:01:59,413 - cc_final_message.py[WARNING]: Used fallback datasource
...
```
## Environment details
- Cloud-init version: 24.1.4
- Operating System Distribution: PhotonOS
- Cloud provider, platform or installer type: NA