Investigate validate check for command defined but not used in event section

MR: Pending

Description

We recently spot one bug for event using command, but the command is not defined.

Then following up on the discussion here, we would like to check the reverse case, where command is defined, but no event is using the command.

Acceptance criteria

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• [Describe what must be achieved to complete this issue.]
• [If applicable, please provide design specifications for this feature/enhancement.]
• [If applicable, please list any technical requirements (performance, security, database, etc.)]

Implementation plan

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