owner, metrics(ticdc): fix metrics (#10459)

[ti-chi-bot]

This is an automated cherry-pick of #10459

What problem does this PR solve?

Issue Number: close #10449, close #10447, close #10438

What is changed and how it works?

1. For #10449, always cleanup metrics whether the changefeed has been cleaned or not.

2. For #10447, use the type of ticdc_kvclient_pull_event_count to distinguish incresmental scan and real-time raft log.

3. For #10438, add changefeedStartTimeGauge metric, which record the changefeed create time and restart time. Note that changefeedStartTimeGauge records the physical time with millisecond precision.

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

`None`.

[CharlesCheung96]

https://github.com/pingcap/tiflow/issues/10449 is batch cherry-pick in https://github.com/pingcap/tiflow/pull/10500. https://github.com/pingcap/tiflow/issues/10447 and https://github.com/pingcap/tiflow/issues/10438 do not need to cherry-pick to release-6.5.

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CharlesCheung96

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[kennytm]

/retest