[WordCard, *Completed] Migrate from deprecated Grid

[imnasnainaec]

Parts of #3879

Notes for review:

• In most places, replaced <Grid> with <Grid2>, <Stack>, <Box>, <div>, or nothing, as fit the design need.
• <Stack direction="row"> can be used in place of <Grid2> when we don't want the items in the row to wrap to a second row in a narrow window

Notes for testing:

• Do a side-by-side visual comparison between this and master (on QA) to make sure appearance is (roughly) the same or (subjectively) improved on all edited components
• Try each edited component with various window widths > 350px (we don't support narrower than that)
• Test *Completed components by clicking a completed goal tile in Data Cleanup under "You've completed:"
  • For MergeDupsCompleted, first go to Data Cleanup > Merge Duplicates, and merge and/or delete words in various combinations
  • For WordCard and ReviewEntriesCompleted, first go to Data Cleanup > Review Entries and edit several entries, including adding multiple semantic domains to a sense
• Test with a few different UI languages

This change is 

[codecov]

Codecov Report

❌ Patch coverage is 58.82353% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.03%. Comparing base (9afcccd) to head (ac8b721).
⚠️ Report is 14 commits behind head on master.

Files with missing lines	Patch %	Lines
src/components/Buttons/UndoButton.tsx	25.00%	3 Missing ⚠️
src/goals/MergeDuplicates/MergeDupsCompleted.tsx	60.00%	2 Missing ⚠️
src/goals/ReviewEntries/ReviewEntriesCompleted.tsx	0.00%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3925   +/-   ##
=======================================
  Coverage   74.03%   74.03%           
=======================================
  Files         288      288           
  Lines       10627    10624    -3     
  Branches     1328     1329    +1     
=======================================
- Hits         7868     7866    -2     
+ Misses       2372     2371    -1     
  Partials      387      387           

Flag	Coverage Δ
backend	85.43% <ø> (ø)
frontend	65.38% <58.82%> (-0.01%)	⬇️

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[jasonleenaylor]

Reviewed 3 of 7 files at r1, 6 of 6 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)