refactor(word): cleanup filter-word-list-by-length.ts

[ST-DDT]

Cleanup some long forgotten code in the words module.

The first part was not used because we shipped TS4 at that time.
The later now uses an explicit nullish check instead of a falsy check.

Is this a chore or a refactor?

Found while looking at: #3261

• Lorem EN word.ts contains a single character in the pool #3261

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.96%. Comparing base (b0a5ad3) to head (02348a3).
Report is 3 commits behind head on next.

Additional details and impacted files

@@           Coverage Diff           @@
##             next    #3262   +/-   ##
=======================================
  Coverage   99.96%   99.96%           
=======================================
  Files        2806     2806           
  Lines      217156   217156           
  Branches      976      975    -1     
=======================================
+ Hits       217075   217078    +3     
+ Misses         81       78    -3     

Files with missing lines	Coverage Δ
src/modules/word/filter-word-list-by-length.ts	100.00% <100.00%> (ø)

... and 2 files with indirect coverage changes

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[Shinigami92]

It's a refactor if length was previously explicitly checked against 0