fix fetch support for node < 18.14.0

[KhafraDev]

Fixes #3123

I'm wondering if we should drop support for node < v18.17.0. The person who reported it mentioned that we can't run the test suite, so there's no way to guarantee that old v18 versions stay supported.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 39.53488% with 26 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.09%. Comparing base (f979ec3) to head (15bdaa6).
⚠️ Report is 1000 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/web/fetch/index.js	38.09%	26 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3124      +/-   ##
==========================================
- Coverage   94.18%   94.09%   -0.10%     
==========================================
  Files          89       89              
  Lines       24379    24418      +39     
==========================================
+ Hits        22962    22975      +13     
- Misses       1417     1443      +26     

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[KhafraDev]

I'm making an alternative to this PR to drop node support for < v18.17.0

[KhafraDev]

#3125 is a better solution IMO, also lets us drop the entire custom File implementation.

[mcollina]

Unless we can test it, it doesn't exists. We should just drop everything under v18.17.0