Should we confirm amount matches commitment in Dbc::confirm_valid()?

[dan-da]

Should we also call self.confirm_provided_amount_matches_commitment(..)?

_Originally posted by @davidrusu in https://github.com/maidsafe/sn_dbc/pull/121#discussion_r805205141_

danda:

maybe, but that would be "invalid" in a different sense than other confirm_valid() errors.

Presently we can distinguish between:

Dbc is valid and amount secrets are valid Dbc is valid and amount secrets are invalid Dbc is invalid and amount secrete are invalid Dbc is invalid and amount secrets are valid

Of these, I think 1 and 2 are most important. Not much need to distinguish between 3 and 4 usually I guess.

One way to retain same granularity would be to return an Enum from confirm_valid() instead of just ().

Or maybe we just keep the present API.

[dan-da]

see also: https://github.com/maidsafe/sn_dbc/pull/121#discussion_r805207503

[dan-da]

addressed by #150