puller: close kvclient correctly when stopping a processor (#11957)

[ti-chi-bot]

This is an automated cherry-pick of #11957

What problem does this PR solve?

Issue Number: close #11954

What is changed and how it works?

When stopping a processor, close the associated puller.

Check List

Tests

• Manual test (add detailed scripts or steps below)

[2024/12/31 16:21:32.261 +08:00] [INFO] [multiplexing_puller.go:331] ["MultiplexingPuller exits"] [namespace=default] [changefeed=x3_owner_ddl_puller]
[2024/12/31 16:21:32.270 +08:00] [INFO] [multiplexing_puller.go:366] ["MultiplexingPuller is closed"] [namespace=default] [changefeed=x3_owner_ddl_puller]
[2024/12/31 16:21:32.273 +08:00] [INFO] [multiplexing_puller.go:331] ["MultiplexingPuller exits"] [namespace=default] [changefeed=x3]
[2024/12/31 16:21:32.273 +08:00] [INFO] [multiplexing_puller.go:366] ["MultiplexingPuller is closed"] [namespace=default] [changefeed=x3]
[2024/12/31 16:21:32.273 +08:00] [INFO] [multiplexing_puller.go:331] ["MultiplexingPuller exits"] [namespace=default] [changefeed=x3_processor_ddl_puller]
[2024/12/31 16:21:32.273 +08:00] [INFO] [multiplexing_puller.go:366] ["MultiplexingPuller is closed"] [namespace=default] [changefeed=x3_processor_ddl_puller]

With the patch, when removing a changefeed, all pullers for owner_ddl, processor_ddl and source_manager are closed.
No goroutine leak happens any more.

Questions

Will it cause performance regression or break compatibility?

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

Release note

None

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hicqu

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[hicqu]

/retest

[hicqu]

/retest

[hicqu]

/retest