chore: compile web3.js tests with the same compiler as the build itself

[steveluscher]

Problem

You can use modern TypeScript language features in the code (like ?? and ?.) but if you try to run the tests they'll explode.

UNTIL NOW.

Summary of Changes

Use the same compiler for the tests as we do for the production build.

[codecov]

Codecov Report

Merging #24728 (f3e5640) into master (8ba003a) will decrease coverage by 11.7%.
The diff coverage is n/a.

❗ Current head f3e5640 differs from pull request most recent head ecfe74d. Consider uploading reports for the commit ecfe74d to get more accurate results

@@             Coverage Diff             @@
##           master   #24728       +/-   ##
===========================================
- Coverage    81.8%    70.0%    -11.8%     
===========================================
  Files         632       37      -595     
  Lines      167499     2301   -165198     
  Branches      322      325        +3     
===========================================
- Hits       137169     1613   -135556     
+ Misses      30217      573    -29644     
- Partials      113      115        +2     

[jstarry]

thank you thank you thank you