[BUGFIX] Solution for /unmute command failing

[janssensjelle]

Types of changes

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• Bugfix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality not to work as expected).
• Documentation Update (if none of the other choices applies).

Proposed changes

When an /unmute command is actioned, the unmute will only remove the muted role. The actual timeout is not removed. This PR fixes that. Might also cause improvement for #49

Checklist

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• I have read and followed the CONTRIBUTING.md
  doc.
• Lint and unit tests pass locally with my changes.
• I have added the necessary documentation (if appropriate).

Additional context