[Random Reader Refactoring] Enable new reader implementation by default

[Tulsishah]

Description

• Enable new reader implementation by default

Link to the issue in case of a bug fix.

Testing details

1. Manual - NA
2. Unit tests - NA
3. Integration tests - Automated
4. Composite tests - Automated
5. Perf tests
   i. Flat bucket
   
   ii. Zonal bucket
   

Any backward incompatible change? If so, please explain.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.87%. Comparing base (a95f8a8) to head (b14bfd7).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3402      +/-   ##
==========================================
+ Coverage   78.84%   78.87%   +0.02%     
==========================================
  Files         140      140              
  Lines       18470    18470              
==========================================
+ Hits        14563    14568       +5     
+ Misses       3423     3420       -3     
+ Partials      484      482       -2     

Flag	Coverage Δ
unittests	78.87% <ø> (+0.02%)	⬆️

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