Circuit creation should fail when circuit is different from prover circuit description

[moCello]

Describe the bug When creating a circuit that is valid in itself but differs from the circuit from the circuit description by adding public inputs to the constraints, the proof creation is successful.

To Reproduce if applicable add a minimum reproducible example

use dusk_plonk::prelude::*;
use rand::rngs::StdRng;
use rand::SeedableRng;

const CAPACITY: usize = 1 << 4;
const LABEL: &[u8] = b"check_public_inputs";

#[derive(Default)]
pub struct TestPI {
    public: Vec<BlsScalar>,
    sum: BlsScalar,
}

impl TestPI {
    pub fn new(public: Vec<BlsScalar>, sum: BlsScalar) -> Self {
        Self { public, sum }
    }
}

impl Circuit for TestPI {
    fn circuit<C>(&self, composer: &mut C) -> Result<(), Error>
    where
        C: Composer,
    {
        // this circuit will always have the same amount of gates but different
        // amount of public inputs, depending on the struct data
        let mut sum = C::ZERO;
        for i in 0..2 {
            let constraint = match i < self.public.len() {
                true => Constraint::new()
                    .left(1)
                    .a(sum)
                    .right(1)
                    .b(C::ONE)
                    .public(self.public[i]),
                false => Constraint::new().left(1).a(sum).right(1).b(C::ONE),
            };
            sum = composer.gate_add(constraint);
        }
        let expected_sum = composer.append_witness(self.sum);
        composer.assert_equal(sum, expected_sum);

        Ok(())
    }
}

#[test]
fn public_inputs() {
    let rng = &mut StdRng::seed_from_u64(0x10b);
    let pp = PublicParameters::setup(CAPACITY, rng)
        .expect("Creation of public parameter shouldn't fail");

    // compiling the default version of TestPI, which has no pi
    let (prover, _verifier) = Compiler::compile::<TestPI>(&pp, LABEL)
        .expect("It should be possible to compile the prover and verifier");

    // Create circuit with public inputs
    let pi: Vec<BlsScalar> = [BlsScalar::one(); 2].into();
    let sum = BlsScalar::from(4);
    let circuit = TestPI::new(pi, sum);
    let result = prover.prove(rng, &circuit);
    assert_eq!(
        result,
        Err(Error::PublicInputNotFound { index: 0 }),
        "proof creation for different sized circuit shouldn't be possible"
    );
}

Expected behaviour This is a minor bug since a Verifier, that doesn't expect public input, won't verify a proof that needs public input. Nevertheless, the proof creation shouldn't be possible for a circuit that doesn't match the circuit description of the Prover.