Delete unnecessary readable-stream types

[Mrtenz]

@types/readable-stream includes all the types we need for readable-stream now, so we can remove the custom declarations.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.43%. Comparing base (8ff9427) to head (638642f).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2784   +/-   ##
=======================================
  Coverage   94.43%   94.43%           
=======================================
  Files         483      483           
  Lines       10297    10297           
  Branches     1568     1568           
=======================================
  Hits         9724     9724           
  Misses        573      573           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.