Make waiting VolumeSnapshot to ready process parallel.

[blackpiglet]

Signed-off-by: Xun Jiang jxun@vmware.com

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Does your change fix a particular issue?

Fixes #4879

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• Accepted the DCO. Commits without the DCO will delay acceptance.
• Created a changelog file or added /kind changelog-not-required as a comment on this pull request.
• Updated the corresponding documentation in site/content/docs/main.

[codecov-commenter]

Codecov Report

Merging #4889 (8c70f13) into main (aa71427) will decrease coverage by 0.06%.
The diff coverage is 0.00%.

❗ Current head 8c70f13 differs from pull request most recent head 6421f8a. Consider uploading reports for the commit 6421f8a to get more accurate results

@@            Coverage Diff             @@
##             main    #4889      +/-   ##
==========================================
- Coverage   41.37%   41.30%   -0.07%     
==========================================
  Files         204      204              
  Lines       17943    17972      +29     
==========================================
  Hits         7424     7424              
- Misses       9972    10001      +29     
  Partials      547      547              

Impacted Files	Coverage Δ
pkg/cmd/server/server.go	6.89% <0.00%> (-0.02%)	⬇️
pkg/controller/backup_controller.go	55.33% <0.00%> (-2.67%)	⬇️

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[reasonerjt]

lgtm, thanks