playground: refine ready message

[xhebox]

What problem does this PR solve?

https://github.com/pingcap/tiup/pull/2202#issuecomment-1689386442

Check List

Tests

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

Code changes

• Has exported function/method change
• Has exported variable/fields change
• Has interface methods change
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation

Release notes:

NONE

[codecov-commenter]

Codecov Report

Patch coverage: 57.14% and no project coverage change.

Comparison is base (eee25bb) 55.83% compared to head (a599bc3) 55.83%.

:exclamation: Current head a599bc3 differs from pull request most recent head 42cd979. Consider uploading reports for the commit 42cd979 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2262 +/- ## ========================================== - Coverage 55.83% 55.83% -0.00% ========================================== Files 321 321 Lines 34017 34022 +5 ========================================== + Hits 18991 18993 +2 - Misses 12754 12755 +1 - Partials 2272 2274 +2 ``` | [Flag](https://app.codecov.io/gh/pingcap/tiup/pull/2262/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [playground](https://app.codecov.io/gh/pingcap/tiup/pull/2262/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `15.71% <57.14%> (+0.01%)` | :arrow_up: | | [tiup](https://app.codecov.io/gh/pingcap/tiup/pull/2262/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `15.86% <ø> (ø)` | | | [unittest](https://app.codecov.io/gh/pingcap/tiup/pull/2262/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `22.58% <0.00%> (-0.01%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap#carryforward-flags-in-the-pull-request-comment) to find out more. | [Files Changed](https://app.codecov.io/gh/pingcap/tiup/pull/2262?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [components/playground/playground.go](https://app.codecov.io/gh/pingcap/tiup/pull/2262?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap#diff-Y29tcG9uZW50cy9wbGF5Z3JvdW5kL3BsYXlncm91bmQuZ28=) | `46.01% <50.00%> (-0.03%)` | :arrow_down: | | [components/playground/main.go](https://app.codecov.io/gh/pingcap/tiup/pull/2262?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap#diff-Y29tcG9uZW50cy9wbGF5Z3JvdW5kL21haW4uZ28=) | `59.42% <100.00%> (ø)` | |

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[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kaaaaaaang

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/pingcap/tiup/blob/master/OWNERS)~~ [kaaaaaaang] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2023-08-24 18:52:17.671867911 +0000 UTC m=+1434702.220883883: :ballot_box_with_check: agreed by kaaaaaaang.
• 2023-08-24 18:52:35.93019914 +0000 UTC m=+1434720.479215112: :heavy_multiplication_x::repeat: reset by kaaaaaaang.
• 2023-08-25 10:31:56.057719898 +0000 UTC m=+1491080.606735870: :ballot_box_with_check: agreed by kaaaaaaang.