fix: redshift dedup pick latest entry

[achettyiitr]

Description

• In case of duplicate entries, always try to pick the latest entries.

Notion Ticket

https://www.notion.so/rudderstacks/redshift-dedup-pick-latest-entry-4c3bbcc8e91e4272865cee051c1f02c2?pvs=4

Security

• The code changed/added as part of this pull request won't create any security issues with how the software is being used.

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.09 ⚠️

Comparison is base (5c27ac2) 68.02% compared to head (234af4b) 67.94%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3603      +/-   ##
==========================================
- Coverage   68.02%   67.94%   -0.09%     
==========================================
  Files         318      318              
  Lines       50375    50375              
==========================================
- Hits        34269    34227      -42     
- Misses      13875    13916      +41     
- Partials     2231     2232       +1     

Impacted Files	Coverage Δ
warehouse/integrations/redshift/redshift.go	66.69% <100.00%> (ø)

... and 7 files with indirect coverage changes

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