BDK shouldn't complain if there are duplicated keys in TapLeaves

[danielabrozzoni]

Describe the bug
BDK returns an error if there are duplicated keys in different tap leaves

To Reproduce
Trying to create a wallet using the descriptor

tr(020202020202020202020202020202020202020202020202020202020202020202,{thresh(1,pk(tpubD6NzVbkrYhZ4WrjhC6iLoEYLhozBrsUjMU4poViXC57heJ8Q3EimPpoUrUKvajtkgfuPpf8Hku7X4sBazDFKqTAiSzGUaK2iCga42pcaFWe),s:pk(tpubD6NzVbkrYhZ4Y2eyqr1oFLQN1c9WUBVu9PyPxKQKnffx5wC1sumGAV9KK2zUj46oDyNCD3GHcfR9e23nFaioBfoBN9a2TtdLoSkKXw9bW1r)),and_v(v:thresh(1,pk(tpubD6NzVbkrYhZ4WrjhC6iLoEYLhozBrsUjMU4poViXC57heJ8Q3EimPpoUrUKvajtkgfuPpf8Hku7X4sBazDFKqTAiSzGUaK2iCga42pcaFWe),s:pk(tpubD6NzVbkrYhZ4Y2eyqr1oFLQN1c9WUBVu9PyPxKQKnffx5wC1sumGAV9KK2zUj46oDyNCD3GHcfR9e23nFaioBfoBN9a2TtdLoSkKXw9bW1r)),older(1))})#kgu06739

will give back Error: Descriptor(DuplicatedKeys), even tho the duplicated keys are in different tap leaves, which should be fine

The descriptor has been created like this:

    let keys = [
        "tpubD6NzVbkrYhZ4WrjhC6iLoEYLhozBrsUjMU4poViXC57heJ8Q3EimPpoUrUKvajtkgfuPpf8Hku7X4sBazDFKqTAiSzGUaK2iCga42pcaFWe",
        "tpubD6NzVbkrYhZ4Y2eyqr1oFLQN1c9WUBVu9PyPxKQKnffx5wC1sumGAV9KK2zUj46oDyNCD3GHcfR9e23nFaioBfoBN9a2TtdLoSkKXw9bW1r",
    ];

    let keys_joined: String = keys.into_iter().map(|k| format!("pk({})", k)).collect::<Vec<_>>().join(",");

    let first_policy_str = format!("thresh({},{})", keys.len() - 1, keys_joined);
    let first_policy = Concrete::<String>::from_str(&first_policy_str)?.compile()?;
    let first_tap_leaf = TapTree::Leaf(Arc::new(first_policy));

    let second_policy_str = format!("and(older(1),thresh({},{}))",keys.len() / 2, keys_joined);
    let second_policy = Concrete::<String>::from_str(&second_policy_str)?.compile()?;
    let second_tap_leaf = TapTree::Leaf(Arc::new(second_policy));

    let dummy_internal = "020202020202020202020202020202020202020202020202020202020202020202".to_string();
    let tap_tree = TapTree::Tree(Arc::new(first_tap_leaf), Arc::new(second_tap_leaf));
    let descriptor = Descriptor::new_tr(dummy_internal, Some(tap_tree))?;
    println!("{}", descriptor);

Expected behavior
The wallet is created normally

Build environment

• BDK tag/commit: v0.22