test(wallet): check there are no duplicates across required and optional utxos

test(wallet): check there are no duplicates across required and optional utxos

This test replaces the one used to test
`coin_selection::filter_duplicates` introduced in
5299db34cb9117ad1b66a6afcb51f6ca7e1f0d95.

As the code changed and there is not a single point to verificate the
following properties:
- there are no duplicates in required utxos
- there are no duplicates in optional utxos
- there are no duplicates across optional and required utxos
anymore, test have been prefixed with `not_duplicated_utxos*` to allow
its joint execution by using the following command:
cargo test -- not_duplicated_utxos