Feat: parallel init cluster info

[yyzxw]

Description of your changes

🤖 Generated by Copilot at b5ef09e

Summary

🚀🙌🔗

Improve multicluster initialization performance and error handling by using errgroup to parallelize cluster version queries in virtual_cluster.go.

We are the multicluster, we rise from the ashes
We use the errgroup to unleash our power
We fetch the versions in parallel, we defy the order
We handle the errors with grace, we are the multicluster

Walkthrough

• Parallelize cluster version fetching using errgroup.Group ([link](https://github.com/kubevela/kubevela/pull/6060/files?diff=unified&w=0#diff-3b863babb08434dd0a998f7b6f89e87f139420f288089d65b778e67595259cb8R25-R26), [link](https://github.com/kubevela/kubevela/pull/6060/files?diff=unified&w=0#diff-3b863babb08434dd0a998f7b6f89e87f139420f288089d65b778e67595259cb8L65-R78))

In my case, if there are a lot of virtual clusters (secrets), but their corresponding clusters are temporarily disconnected, this will eventually cause the context to time out, and the requests will accumulate, causing the controller to take a long time to restart, This causes the controller to be rebooted frequently because the ready probe is not satisfied. Therefore, cluster information is initialized in parallel to accelerate the startup speed of controller.

Fixes #

I have:

• Read and followed KubeVela's contribution process.
• Related Docs updated properly. In a new feature or configuration option, an update to the documentation is necessary.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

Special notes for your reviewer

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.03 ⚠️

Comparison is base (c039328) 61.00% compared to head (cfe48ff) 60.97%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6060      +/-   ##
==========================================
- Coverage   61.00%   60.97%   -0.03%     
==========================================
  Files         224      224              
  Lines       31274    31274              
==========================================
- Hits        19079    19070       -9     
- Misses      10430    10432       +2     
- Partials     1765     1772       +7     

Flag	Coverage Δ
core-unittests	56.09% <0.00%> (-0.10%)	⬇️
e2e-multicluster-test	22.86% <100.00%> (-2.10%)	⬇️
e2etests	25.17% <100.00%> (+0.15%)	⬆️

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

Impacted Files	Coverage Δ
pkg/multicluster/virtual_cluster.go	79.41% <100.00%> (ø)

... and 16 files with indirect coverage changes

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[yyzxw]

/retest go