ebs br: serial execution of volume backup gc (#5452)

[ti-chi-bot]

This is an automated cherry-pick of #5452

What problem does this PR solve?

Closes #5451

What is changed and how does it work?

This PR make the EBS snapshot volume backup GC execute serially. In the single volumebackup, delete snapshots in batches.

Code changes

• Has Go code change
• Has CI related scripts change

Tests

• Unit test
• E2E test
• Manual test
• No code

Side effects

• Breaking backward compatibility
• Other side effects:

Related changes

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

Release Notes

Please refer to Release Notes Language Style Guide before writing the release note.

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[codecov-commenter]

Codecov Report

Merging #5473 (ea66952) into release-1.5 (29b6292) will increase coverage by 0.00%.
The diff coverage is 28.57%.

Additional details and impacted files

@@             Coverage Diff              @@
##           release-1.5    #5473   +/-   ##
============================================
  Coverage        61.66%   61.66%           
============================================
  Files              228      228           
  Lines            29096    29106   +10     
============================================
+ Hits             17942    17949    +7     
+ Misses            9394     9393    -1     
- Partials          1760     1764    +4     

Flag	Coverage Δ
unittest	61.66% <28.57%> (+<0.01%)	⬆️