fix: Include warnings for restore failures

[lowlydba]

Description

There is some contextual info that is relevant for debugging database restores that only appears as warning logs in dbatools, thereby not making it natively accessible to Ansible.

Append the warnings for the restore command to the failure json to increase usability.

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue) - Fixes Error handling / Output (see warnings for details. ) #263
• New feature (non-breaking change which adds functionality)

Checklist:

• I have read/followed the CONTRIBUTING document.
• I have read/followed the PR Quick Start Guide
• I have added tests to cover my changes or they are N/A.
• I have added a changelog fragment describing the changes.
• New module options/parameters include a version_added property.