T6534: fix incorrect imports in vyos-config-encrypt.py (backport #3743)

[mergify]

Change Summary

When executing command encryption enable, the command fails with:

Traceback (most recent call last):
  File "/usr/libexec/vyos/vyos-config-encrypt.py", line 29, in <module>
    from vyos.util import ask_input
ModuleNotFoundError: No module named 'vyos.util'

This is due to incorrect python imports (from vyos.util import ask_input instead of from vyos.utils.io import ask_input). This PR fixes this.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

https://vyos.dev/T6534

Related PR(s)

none

Component(s) name

encryption

Proposed changes

Fix incorrect python imports.

How to test

Execute encryption enable.

Smoketest result

There is no smoketest for this. I've build qemu-live image, here's the cmd output:

vyos@vyos:~$ encryption enable
WARNING: VyOS will boot into a default config when encrypted without a TPM
You will need to manually login with default credentials and use "encryption load"
to mount the encrypted volume and use "load /config/config.boot"

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

---

This is an automatic backport of pull request #3743 done by [Mergify](https://mergify.com).

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