Only set message_id when provided by caller

[princjef]

Description

When sending events using the Node.js Event Hubs SDK, it automatically adds the message_id property if one is not specified. This is not the same as the behavior in the .NET SDK and leads to some inconsistency in the received messages sent by the various SDKs.

This PR removes the default ids from the sent messages and updates the unit tests to check both variations to ensure that the id is set correctly. It also tweaks the relevant tests to receive from an offset rather than a time to make them more reliable.

[amarzavery]

✅ Validation status: passed

File	Status	Preview URL	Details
client/lib/eventData.ts	✅Succeeded
client/lib/eventHubSender.ts	✅Succeeded
client/tests/misc.spec.ts	✅Succeeded

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