[3.9.0] Address cluster update failure when old capacity reservation has been deleted

[hgreebe]

Description of changes

• Cherry-pick of [3.13.1] Address cluster update failure when old capacity reservation has been deleted #6867

Tests

• Ran released.yaml integ tests

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 90.20%. Comparing base (011616c) to head (68af33b).
Report is 2 commits behind head on integ-tests-3.9.0.

Files with missing lines	Patch %	Lines
cli/src/pcluster/config/cluster_config.py	66.66%	2 Missing ⚠️

Additional details and impacted files

@@                  Coverage Diff                  @@
##           integ-tests-3.9.0    #6880      +/-   ##
=====================================================
- Coverage              90.21%   90.20%   -0.02%     
=====================================================
  Files                    181      181              
  Lines                  15838    15840       +2     
=====================================================
  Hits                   14288    14288              
- Misses                  1550     1552       +2     

Flag	Coverage Δ
unittests	90.20% <66.66%> (-0.02%)	⬇️

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