perf(wallet): only do extra MSMP verification in debug mode

This small change gives a 2x speedup on the wallet-updating process,
as evidenced by the wallet-state update benchmark which.i

**Before this commit**
Timer precision: 20 ns
wallet_state                   fastest       │ slowest       │ median        │ mean          │ samples │ iters
╰─ maintain_membership_proofs                │               │               │               │         │
   ╰─ maintain_100_100                       │               │               │               │         │
      ╰─ apply_block2          172.2 ms      │ 184.5 ms      │ 175.6 ms      │ 176.2 ms      │ 10      │ 10

**After this commit**
Timer precision: 20 ns
wallet_state                   fastest       │ slowest       │ median        │ mean          │ samples │ iters
╰─ maintain_membership_proofs                │               │               │               │         │
   ╰─ maintain_100_100                       │               │               │               │         │
      ╰─ apply_block2          91.05 ms      │ 102.8 ms      │ 91.97 ms      │ 92.91 ms      │ 10      │ 10

Author: Sword-Smith

src/util_types/mutator_set/ms_membership_proof.rs

@@ -98,7 +98,7 @@ impl MsMembershipProof {
             "Function must be called with same number of membership proofs and items. Got {} items and {} membership proofs", own_items.len(), membership_proofs.len()
         );
 
-        assert!(membership_proofs
+        debug_assert!(membership_proofs
             .iter()
             .all(|msmp| msmp
                 .target_chunks