PARTIAL: cargo lint on benchmarks

Refs #3556

crates/bench/benches/undelegate_claim.rs

@@ -1,14 +1,15 @@
 use ark_ff::UniformRand;
 use ark_relations::r1cs::{
-    ConstraintSynthesizer, ConstraintSystem, OptimizationGoal, SynthesisMode,
+    ConstraintSystem, OptimizationGoal, SynthesisMode,
 };
 use decaf377::{Fq, Fr};
 use decaf377_rdsa as rdsa;
 use penumbra_asset::{asset, balance};
 use penumbra_num::Amount;
 use penumbra_proof_params::UNDELEGATECLAIM_PROOF_PROVING_KEY;
+use penumbra_shielded_pool::ConvertCircuit;
 use penumbra_stake::{
-    IdentityKey, Penalty, UnbondingToken, UndelegateClaimCircuit, UndelegateClaimProof,
+    IdentityKey, Penalty, UnbondingToken, UndelegateClaimProof,
 };
 
 use criterion::{criterion_group, criterion_main, Criterion};
@@ -67,7 +68,7 @@ fn undelegate_claim_proving_time(c: &mut Criterion) {
     });
 
     // Also print out the number of constraints.
-    let circuit = UndelegateClaimCircuit::new(
+    let circuit = ConvertCircuit::new(
         unbonding_amount,
         balance_blinding,
         balance_commitment,