api(ticdc): only update upstreamInfo that has changed (#10422)

[ti-chi-bot]

This is an automated cherry-pick of #10422

What problem does this PR solve?

Issue Number: close #10430

What is changed and how it works?

there are two apis that update or create upstream information:

1. create changfeed and upstreamPUT /api/v2/changefeeds/{changefeed_id}
2. update changefeed and upstream POST /api/v2/changefeeds

And, the expected usage of these apis is:

1. Avoid modifying the same changefeed concurrently .
2. Avoid modifying the same upstream concurrently.

Before this PR, when a changefeed is created, cdc always updates the uptream information, regardless of whether the uptream changes. As a result, when different ChangeFeeds are created concurrently, cdc conflicts with concurrent updates to the same upstream key.

To solve this issue, we should only update upstreamInfo that has changed when creating changefeed.

---

Besides, cdc did not perform any checks when updating changefeed info:

tiflow/pkg/etcd/etcd.go

Line 513 in c6b3fec

resp, err := c.Client.Txn(ctx, txnEmptyCmps, opsThen, TxnEmptyOpsElse)

To prevent concurrent updates to the same changefeed, we should compare the versions of the info and status keys.

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

`Fix a issue that TiCDC return ErrChangeFeedAlreadyExists when changefeeds are created concurrently`.

[ti-chi-bot]

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This pull-request has been approved by: CharlesCheung96

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