fix(plugin-meetings): fix for orphaned meeting

[shnaaz]

COMPLETES #< INSERT LINK TO ISSUE >

https://jira-eng-gpk2.cisco.com/jira/browse/SPARK-776971

This pull request addresses

< DESCRIBE THE CONTEXT OF THE ISSUE >
Only emit MEETING_ADDED if the meeting still exists in the collection.
If fetchMeetingInfo failed and the meeting was destroyed in the catch block,
skip emitting to prevent orphaned meeting references on the consumer side.

by making the following changes

< DESCRIBE YOUR CHANGES >

Change Type

• Bug fix (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 to change)
• Documentation update
• Tooling change
• Internal code refactor

The following scenarios were tested

< ENUMERATE TESTS PERFORMED, WHETHER MANUAL OR AUTOMATED >

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