* unknownproto: check result from protowire.ConsumeFieldValue and return error
Given that protowire.ConsumeFieldValue returns -1 when it encounters an
error, perform a check for n < 0 and return the respectively obtained
error with context about the details.
Fixes an issue identified from a go-fuzz session, thanks to Ethan
Buchman and the IBC auditors from Informal Systems et al.
Fixes#7739.
* Address AlexanderBez's suggestions
* Use require in tests
* Add issue #7846 to TODO
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
Emmanuel T Odeke