crypto: fix multi-prime RSA JWKs

[panva]

This fixes inconsistent multi-prime RSA key handling between PKCS#8 and JWK formats.

Operation	Node.js 24.x	Node.js 26.x / main	This PR
PKCS#8 → PKCS#8	Preserves all primes	Preserves all primes	Preserves all primes
PKCS#8 → JWK	Omits oth	Omits oth	Includes oth
JWK import	Accepts but discards oth	Rejects because n != p * q	Imports all primes
JWK → PKCS#8	Produces an invalid two-prime key	Not reachable	Preserves the original key
Sign after JWK import	Works through OpenSSL's non-CRT fallback	Not reachable	Works with the complete key

[nodejs-github-bot]

Review requested:

• @nodejs/crypto
• @nodejs/security-wg

[codecov]

Codecov Report

❌ Patch coverage is 61.25000% with 31 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.04%. Comparing base (789c7fd) to head (3c56d9f).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
src/crypto/crypto_rsa.cc	61.25%	12 Missing and 19 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #65649      +/-   ##
==========================================
- Coverage   90.05%   90.04%   -0.01%     
==========================================
  Files         754      754              
  Lines      255727   255813      +86     
  Branches    48320    48343      +23     
==========================================
+ Hits       230300   230357      +57     
- Misses      16552    16565      +13     
- Partials     8875     8891      +16     

Files with missing lines	Coverage Δ
src/crypto/crypto_rsa.cc	64.21% <61.25%> (-0.94%)	⬇️

... and 34 files with indirect coverage changes

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[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/76719/