eventcollector: clarify dispatcher session state transitions

[lidezhu]

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[gemini-code-assist]

Code Review

This pull request refactors the dispatcherSession and dispatcherConnState logic to implement a more robust state machine for managing dispatcher registrations, specifically improving the coordination between local and remote event services and ensuring the cleanup of stale registrations. The review feedback identified minor typos in the documentation comments within dispatcher_session.go and provided a suggestion for correction.

[gemini-code-assist]

There are a couple of typos in this comment. reduduant should be redundant and syncpoint should be sync point.

Suggested change

	// after reset during normal run time, we can filter reduduant syncpoint at event collector side
	// so we just take care of the case that resetTs is same as startTs
	// after reset during normal run time, we can filter redundant sync points at event collector side
	// so we just take care of the case that resetTs is same as startTs

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