playground: fix panic when boot monitor

[nexustar]

What problem does this PR solve?

• fix playground panic when boot monitor #1711

What is changed and how it works?

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

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• AstroProfundis

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[codecov-commenter]

Codecov Report

Merging #1712 (1b46df1) into master (e7e5689) will increase coverage by 28.65%.
The diff coverage is 66.67%.

@@             Coverage Diff             @@
##           master    #1712       +/-   ##
===========================================
+ Coverage   24.48%   53.12%   +28.65%     
===========================================
  Files         277      303       +26     
  Lines       31419    34649     +3230     
===========================================
+ Hits         7690    18407    +10717     
+ Misses      22877    14094     -8783     
- Partials      852     2148     +1296     

Flag	Coverage Δ
playground	12.73% <66.67%> (?)
tiup	14.58% <ø> (ø)
unittest	21.36% <0.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
components/playground/playground.go	49.05% <66.67%> (+49.05%)	⬆️
pkg/cluster/ansible/service.go	4.26% <0.00%> (-0.34%)	⬇️
pkg/logger/logger.go	100.00% <0.00%> (ø)
components/playground/instance/tikv_config.go	100.00% <0.00%> (ø)
pkg/cluster/operation/destroy.go	59.40% <0.00%> (ø)
components/playground/instance/tiflash_config.go	70.59% <0.00%> (ø)
pkg/cluster/operation/check.go	50.97% <0.00%> (ø)
pkg/cluster/operation/upgrade.go	54.72% <0.00%> (ø)
components/playground/instance/pd.go	73.02% <0.00%> (ø)
pkg/cluster/operation/download.go	33.33% <0.00%> (ø)
... and 217 more

---

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[AstroProfundis]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 1b46df1