Remove unused func and unnecessary shim

[tsctx]

I have removed unused and unreachable code paths.
The shim for WebSocket crypto.randomFillSync is no longer required since SHA-1 (essential for WebSocket functionality) cannot be used in environments without crypto support.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.10%. Comparing base (a516f87) to head (2d75925).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5053      +/-   ##
==========================================
+ Coverage   93.08%   93.10%   +0.02%     
==========================================
  Files         110      110              
  Lines       35804    35775      -29     
==========================================
- Hits        33327    33308      -19     
+ Misses       2477     2467      -10     

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[mcollina]

lgtm