build: DH-21044: Disable pre/post install scripts (#2586)

[mofojed]

• Pre/post install scripts was something Sha1-hulud used to propagate
• Just disable them
• Updated scripts to ensure npm install then npm start/npm run build/npm run test all work correctly

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 48.44%. Comparing base (3ad471d) to head (1a3884d).

Additional details and impacted files

@@               Coverage Diff               @@
##           release/v0.85    #2596    +/-   ##
===============================================
  Coverage          48.44%   48.44%            
===============================================
  Files                712      712            
  Lines              39747    39747            
  Branches            9921    10112   +191     
===============================================
  Hits               19255    19255            
  Misses             20479    20479            
  Partials              13       13            

Flag	Coverage Δ
unit	48.44% <ø> (ø)

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