fix(MQTT Trigger Node): Fix typo (no-changelog)

[craSH]

Summary

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This simply fixes a one-character typo in the MQTT Trigger's Topic Description/Tooltip. colom -> colon.

Related tickets and issues

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Review / Merge checklist

• [x] PR title and summary are descriptive. Remember, the title automatically goes into the changelog. Use (no-changelog) otherwise. (conventions)
• [x] Docs updated or follow-up ticket created.
• [ ] Tests included.
  • N/A