test(cketh): expect the status a failed funding actually reports

The dedicated Failed status was reverted after review: it meant adding a
variant to retrieve_eth_status' return type, breaking existing clients, to
describe a state mainnet cannot reach — a bare transfer to a code-less address
the minter's own key controls has nothing to revert in.

This test reaches it anyway, by placing reverting code at the sweeper, so it
now expects the pending-reimbursement status and says why that label is
tolerated. What it asserts either way is the invariant: no reimbursement, and
the burn stays as prepaid gas.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: mbjorkqvist

rs/ethereum/cketh/minter/tests/sweeper_funding_hardening.rs

@@ -163,10 +163,15 @@ fn should_not_reimburse_a_funding_transaction_that_fails_on_chain() {
     // what happens when it fails.
     setup.await_funding_finalized(FINALIZATION_DEADLINE);
     let status = setup.withdrawal_status(burn_index);
+    // Pending reimbursement is imprecise here — nothing will ever settle it — and deliberately so:
+    // a status of its own meant adding a variant to `retrieve_eth_status`, which breaks every
+    // existing client, to describe a state mainnet cannot reach. This test reaches it only by
+    // placing code at an address derived from the minter's own key. The invariant that actually
+    // matters is asserted below: the burn is never paid back.
     assert!(
-        status.starts_with("Failed("),
-        "a failed funding must report Failed, not a reimbursement that never comes, got {status} \
-         (sweeper {sweeper}, {} bytes of code, balance {})",
+        status.starts_with("PendingReimbursement("),
+        "unexpected status for a failed funding: {status} (sweeper {sweeper}, {} bytes of code, \
+         balance {})",
         setup.code(&sweeper).len(),
         setup.anvil_eth_balance(&sweeper),
     );