[MergeDups] Migrate from deprecated Grid

[imnasnainaec]

Part of #3879

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This change is 

[codecov]

Codecov Report

❌ Patch coverage is 40.00000% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.07%. Comparing base (efbfe3c) to head (15b2344).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...geDuplicates/MergeDupsStep/MergeDragDrop/index.tsx	50.00%	2 Missing ⚠️
...MergeDuplicates/MergeDupsStep/SaveDeferButtons.tsx	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3930      +/-   ##
==========================================
+ Coverage   74.03%   74.07%   +0.03%     
==========================================
  Files         288      288              
  Lines       10624    10624              
  Branches     1329     1329              
==========================================
+ Hits         7866     7870       +4     
+ Misses       2371     2368       -3     
+ Partials      387      386       -1     

Flag	Coverage Δ
backend	85.52% <ø> (+0.08%)	⬆️
frontend	65.38% <40.00%> (ø)

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[jasonleenaylor]

Reviewed 5 of 5 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)