Consistent buffer_size_limit assertions

[ionut-arm]

The handling of the admin-set maximum buffer size (for responses) is inconsistent - some operations perform the check (e.g., psa_generate_random in the MbedCrypto provider), others do not (e.g., psa_generate_random in the TPM provider). Ideally, this should be checked consistently, for every (successful) response about to be sent out. We need to figure out if we want to impose this check on other buffers as well (for example, on the output of symmetric encryption or decryption operations).