fix(elasticache): improve logic in elasticache_redis_cluster_backup_enabled

[prowler-bot]

Backport

This will backport the following commits from master to v5.3:

• fix(elasticache): improve logic in `elasticache_redis_cluster_backup_enabled` (#7042)

Questions ?

Please refer to the Backport tool documentation

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.70%. Comparing base (6491bce) to head (0b81efc).
Report is 1 commits behind head on v5.3.

Additional details and impacted files

@@            Coverage Diff             @@
##             v5.3    #7045      +/-   ##
==========================================
- Coverage   88.73%   88.70%   -0.03%     
==========================================
  Files        1200     1200              
  Lines       34826    34826              
==========================================
- Hits        30903    30894       -9     
- Misses       3923     3932       +9     

Flag	Coverage Δ
prowler	88.70% <100.00%> (-0.03%)	⬇️

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Components	Coverage Δ
prowler	88.70% <100.00%> (-0.03%)	⬇️
api	∅ <ø> (∅)