Modified posix builds to enable dilithium by default

[jakemas]

Issues:

Addresses #P175809809

Description of changes:

As we prepare ML-DSA and the removal of the enable_dilithium flag, we prepare our builds to all enable dilithium. This should also catch addition bugs in the CI.

One such bug has already been found by testing this addition, that has also been addressed in this PR:

In file included from /crypto/dilithium/ml_dsa.c:20:
/crypto/dilithium/./pqcrystals_dilithium_ref_common/sign.c: In function ‘crypto_sign_keypair_internal’:
/crypto/dilithium/./pqcrystals_dilithium_ref_common/sign.c:54:9: error: ‘s1’ may be used uninitialized [-Werror=maybe-uninitialized]
 54 | s1hat = s1;
 | ~~~~^~
crypto/dilithium/./pqcrystals_dilithium_ref_common/sign.c:35:12: note: ‘s1’ declared here
 35 | polyvecl s1, s1hat;
 | ^~

Testing:

Found through testing for linux builds/

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.77%. Comparing base (8226a05) to head (729179a).
Report is 25 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2034      +/-   ##
==========================================
+ Coverage   78.67%   78.77%   +0.10%     
==========================================
  Files         598      598              
  Lines      103350   103688     +338     
  Branches    14693    14743      +50     
==========================================
+ Hits        81308    81681     +373     
+ Misses      21389    21353      -36     
- Partials      653      654       +1     

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