Fix linkwarden update

[burgerga]

✍️ Description

This PR fixes linkwarden's update

• Without the rm -rf the mv line that comes after this will result in, for example, /opt/linkwarden/linkwarden-2.9.3 instead of moving the new version to /opt/linkwarden.
• The removal of the linkwarden_bak is because this backup is never created.
• Trailing newline inserted

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✅ Prerequisites

The following steps must be completed for the pull request to be considered:

• Self-review performed (I have reviewed my code to ensure it follows established patterns and conventions.)
• Testing performed (I have thoroughly tested my changes and verified expected functionality.)

🛠️ Type of Change

Please check the relevant options:

• Bug fix (non-breaking change that resolves an issue)
• [] New feature (non-breaking change that adds functionality)
• [] Breaking change (fix or feature that would cause existing functionality to change unexpectedly)
• [] New script (a fully functional and thoroughly tested script or set of scripts)

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📋 Additional Information (optional)

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