metrics(ticdc): add kafka compression ratio description for grafana (#11348)

[ti-chi-bot]

This is an automated cherry-pick of #11348

What problem does this PR solve?

Issue Number: close #11347

What is changed and how it works?

add kafka compression ratio description for grafana

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`.

[ti-chi-bot[bot]]

This cherry pick PR is for a release branch and has not yet been approved by triage owners. Adding the do-not-merge/cherry-pick-not-approved label.

To merge this cherry pick:

1. It must be approved by the approvers firstly.
2. AFTER it has been approved by approvers, please wait for the cherry-pick merging approval from triage owners.

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[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[ti-chi-bot[bot]]

@ti-chi-bot: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-cdc-integration-storage-test	36dbe7c23591462f71ba83cb89f0a1bcd404ad2e	link	true	/test cdc-integration-storage-test
pull-cdc-integration-mysql-test	36dbe7c23591462f71ba83cb89f0a1bcd404ad2e	link	true	/test cdc-integration-mysql-test

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).