Bugfix
   * Add guards in pk_wrap.c to ensure if ECDSA is not defined, errors are
     returned. Remove warnings in pk.c for unused variables. Add new test
     (test_depends_pkalgs_psa) to all.sh to confirm when USE_PSA_CRYPTO 
     is defined that features are working properly. Fixes issue reported in
     #3294 where undefined reference errors occur when using USE_PSA_CRYPTO
     and removing ECDSA support.