Errors in validating ECC key bits in PKCS11 provider

[ionut-arm]

During the development of #170 (PR: #540) a couple of tests were added to validate the parsing of inputs to public ECC key importing. Specifically, the bits field of the key attributes could be "inconsistent" in a number of ways with the size of the key actually being imported:

• if the bits field is 0, then the length of the imported key should be used instead
• if the bits field is a non-zero number, we should ensure that the key matches that size

While running on the CI, however, it became apparent that the PKCS11 provider does not function correctly in either of those circumstances, rejecting the import when the field is 0 and accepting it when a wrong size is provided.