fix(ethereum): deflake monitor timeout tests in l1_tx_utils

[AztecBot]

Problem

l1_tx_utils.test.ts flaked in CI (log, seen on #24454, which is unrelated to the failure). The failing test was monitors all sent txs:

● L1TxUtils › L1TxUtils with blobs › monitors all sent txs
  TimeoutError: L1 transaction 0x82cf...aa3a timed out
      at TestL1TxUtils.monitorTransaction (l1_tx_utils/l1_tx_utils.ts:601:11)

Root cause

The test creates the monitor promise and only attaches its rejection expectation after several intervening awaits:

const monitorPromise = gasUtils.monitorTransaction(state);
await sleep(100);
await cheatCodes.mineEmptyBlock();
await expect(monitorPromise).rejects.toThrow('timed out'); // handler attached here

Anvil timestamps have 1s granularity, so when the wall clock crosses a second boundary between the send and the monitor's timeout check, the monitor (with txTimeoutMs: 200, checkIntervalMs: 100) can observe the L1 timestamp already 1s past sentAt and reject before mineEmptyBlock() completes. In the failing run the timeout fired at 16:41:20.355, before the empty block was mined at .356 and before the .rejects handler attached at .357. Node emitted unhandledRejection in that window and jest 30 reported it as the test failure — which is why the failure stack has no test-file frame and the test's own assertions all passed in the log.

The same file already uses the safe idiom in a dozen newer tests: attach the handler synchronously with .catch(err => err) and assert via resolves.toBeInstanceOf(TimeoutError).

Fix

Apply that established pattern to the three remaining tests that expect a monitor timeout but attach the handler only after intervening awaits:

• stops trying after timeout once block is mined
• attempts to cancel timed out transactions
• monitors all sent txs (the observed flake)

Test-only change; no product code touched. TimeoutError is exactly what monitorTransaction throws on timeout, so the assertions are equivalent-or-stricter than the previous message matching.

Evidence: CI log http://ci.aztec-labs.com/390c881d64e094b6 (search for monitors all sent txs).

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Created by claudebox · group: slackbot