client: update the leader even if the connection creation fails (#7443)

[ti-chi-bot]

This is an automated cherry-pick of #7443

What problem does this PR solve?

Issue Number: Close #7416

What is changed and how does it work?

update the leader even if the connection creation fails.
If connection is nil, consider it as networkErr

Check List

Tests

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

Code changes

• Has the configuration change
• Has HTTP API interfaces changed (Don't forget to add the declarative for the new API)
• Has persistent data change

Side effects

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

Related changes

• PR to update pingcap/docs/pingcap/docs-cn:
• PR to update pingcap/tiup:
• Need to cherry-pick to the release branch

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• CabinfeverB
• JmPotato

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[codecov]

Codecov Report

Merging #7476 (f985468) into release-7.5 (c9c9979) will decrease coverage by 0.04%.
The diff coverage is 100.00%.

❗ Current head f985468 differs from pull request most recent head bbd6a3c. Consider uploading reports for the commit bbd6a3c to get more accurate results

Additional details and impacted files

@@               Coverage Diff               @@
##           release-7.5    #7476      +/-   ##
===============================================
- Coverage        74.74%   74.70%   -0.04%     
===============================================
  Files              443      443              
  Lines            47891    47901      +10     
===============================================
- Hits             35795    35786       -9     
- Misses            8950     8964      +14     
- Partials          3146     3151       +5     

Flag	Coverage Δ
unittests	74.70% <100.00%> (-0.04%)	⬇️

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

[JmPotato]

/merge

[ti-chi-bot]

@JmPotato: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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[ti-chi-bot]

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

Commit hash: c479cf9

[ti-chi-bot]

@ti-chi-bot: Your PR was out of date, I have automatically updated it for you.

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[CabinfeverB]

meet #7551
so I updated golangci-lint version

[CabinfeverB]

/merge

[ti-chi-bot]

@CabinfeverB: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

If you have any questions about the PR merge process, please refer to pr process.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

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

Commit hash: bbd6a3c