Deduplicate credentials to be shared.

[BigBlueHat]

Currently, sending in multiple QueryByExample requests that both/all result in matches will return duplicate credentials. The user will then see 4 credentials on the "share" list when they in fact only have 2 credentials of that type.

The list should be deduplicated so the user never sees more credentials than they have in their wallet.

[BigBlueHat]

This seems to happen when selective disclosure capable cryptosuites are used and multiple QueryByExample queries are made at once. The UI actually treats the duplicates as a single credential, though: clicking the checkbox next to one (un)checks the other also...

This may be a "feature" that just needs more UI work to make it clear what's happening: multiple queries resulting in multiple ways to selectively disclose.