fix: skip npm publish if boa_wasm version already exists

[JkrishnaD]

This Pull Request fixes/closes #4065 .

It changes the following:

• Added npm version check using npm view @boa-dev/boa_wasm@$VERSION
• Skip npm publish step when the version already exists

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	52,862	52,862	0
Passed	49,497	49,497	0
Ignored	2,255	2,255	0
Failed	1,110	1,110	0
Panics	0	0	0
Conformance	93.63%	93.63%	0.00%

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 56.62%. Comparing base (6ddc2b4) to head (fe290c4).
⚠️ Report is 679 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4654      +/-   ##
==========================================
+ Coverage   47.24%   56.62%   +9.37%     
==========================================
  Files         476      548      +72     
  Lines       46892    60083   +13191     
==========================================
+ Hits        22154    34021   +11867     
- Misses      24738    26062    +1324     

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[jedel1043]

Nice, thank you for the fix!