puller: fix remove path

[lidezhu]

What problem does this PR solve?

Issue Number: close #xxx

What is changed and how it works?

After unsubscribe a subscription, there may still be more region events to handle(like region error). So we should remove path in onTableDrained instead.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Questions

Will it cause performance regression or break compatibility?

Do you need to update user documentation, design documentation or monitoring documentation?

Release note

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[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: asddongmen

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-02-08 04:12:57.618043168 +0000 UTC m=+70620.014265230: ☑️ agreed by asddongmen.