fix: remove undeclared dependency on underscore

[raphinesse]

Motivation and Context

This removes usage of underscore that were introduced after merging #772.

Closes #869

Description

I rewrote the two remaining usages of underscore using plain JS.

Testing

Automated test suite

[codecov-commenter]

Codecov Report

Merging #871 (86e1aa4) into master (cf5c487) will decrease coverage by 0.05%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master     #871      +/-   ##
==========================================
- Coverage   91.18%   91.13%   -0.06%     
==========================================
  Files          45       45              
  Lines        2054     2053       -1     
==========================================
- Hits         1873     1871       -2     
- Misses        181      182       +1     

Impacted Files	Coverage Δ
src/cordova/requirements.js	54.54% <0.00%> (-9.10%)	⬇️
src/cordova/serve.js	100.00% <100.00%> (ø)

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