Discard deny listed solver solutions (#2781)

# Description
Currently solvers that get deny listed by the circuit breaker due to
rule violations still receive `/solve` and subsequent `/settle` calls by
the autopilot.

# Changes
Discards any solution returned by `/solve` where the given submission
address is currently deny listed. Since these solutions will no longer
get ranked in the competition we'll also not call `/settle` for them
anymore.

## How to test
e2e tests should still pass
I didn't add the test case that verifies that a deny listed solver
actually gets their solutions removed but if that doesn't work this PR
would not make it worse than the status quo.

crates/autopilot/src/domain/competition/mod.rs

@@ -91,4 +91,6 @@ pub enum SolutionError {
     ZeroScore(#[from] ZeroScore),
     #[error(transparent)]
     InvalidPrice(#[from] auction::InvalidPrice),
+    #[error("the solver got deny listed")]
+    SolverDenyListed,
 }

crates/autopilot/src/run_loop.rs

@@ -371,7 +371,38 @@ impl RunLoop {
         if response.solutions.is_empty() {
             return Err(SolveError::NoSolutions);
         }
-        Ok(response.into_domain())
+        let solutions = response.into_domain();
+
+        // TODO: remove this workaround when implementing #2780
+        // Discard any solutions from solvers that got deny listed in the mean time.
+        let futures = solutions.into_iter().map(|solution| async {
+            let solution = solution?;
+            let solver = solution.solver();
+            let is_allowed = self
+                .eth
+                .contracts()
+                .authenticator()
+                .is_solver(solver.into())
+                .call()
+                .await;
+
+            match is_allowed {
+                Ok(true) => Ok(solution),
+                Ok(false) => Err(domain::competition::SolutionError::SolverDenyListed),
+                Err(err) => {
+                    // log warning but discard solution anyway to be on the safe side
+                    tracing::warn!(
+                        driver = driver.name,
+                        ?solver,
+                        ?err,
+                        "failed to check if solver is deny listed"
+                    );
+                    Err(domain::competition::SolutionError::SolverDenyListed)
+                }
+            }
+        });
+
+        Ok(futures::future::join_all(futures).await)
     }
 
     /// Ask the winning solver to reveal their solution.
@@ -624,6 +655,7 @@ impl Metrics {
         let label = match err {
             SolutionError::ZeroScore(_) => "zero_score",
             SolutionError::InvalidPrice(_) => "invalid_price",
+            SolutionError::SolverDenyListed => "solver_deny_listed",
         };
         Self::get()
             .solutions