test(e2e): narrow down sentinel check in multiple_validators_sentinel (#23604)

Instead of checking a range of slots, we only check the slot we're
interested in. This prevents any build errors that occured until things
got stable from interfering. For instance, the sequencer we stop could
cause the _next_ sequencer to miss their block. Looking just into the
`sentinelSlot` removes this indeterminism.

Author: spalladino

yarn-project/end-to-end/src/e2e_p2p/multiple_validators_sentinel.parallel.test.ts

@@ -214,11 +214,14 @@ describe('e2e_p2p_multiple_validators_sentinel', () => {
     const stats = await sentinel.getValidatorsStats();
     t.logger.info(`Collected validator stats at slot ${t.monitor.l2SlotNumber}`, { stats });
 
-    // Check that all of the first node validators have attestations recorded
+    const historyForSlot = (validator: (typeof firstNodeValidators)[number]) =>
+      stats.stats[validator.toString().toLowerCase()]?.history.filter(h => h.slot === slotForSentinel) ?? [];
+
+    // Check that all of the first node validators have attestations recorded for the selected proposer slot.
     for (const validator of firstNodeValidators) {
-      const validatorStats = stats.stats[validator.toString().toLowerCase()];
-      const history = validatorStats?.history.filter(h => h.slot > initialSlot && h.slot <= slotForSentinel) ?? [];
+      const history = historyForSlot(validator);
       t.logger.info(`Asserting stats for online validator ${validator}`, { history });
+      expect(history).not.toBeEmpty();
       expect(
         history.filter(
           h => h.status === 'attestation-missed' || h.status === 'blocks-missed' || h.status === 'checkpoint-missed',
@@ -229,14 +232,13 @@ describe('e2e_p2p_multiple_validators_sentinel', () => {
     // At least one of the first node validators must have been seen as proposer
     const firstNodeBlockProposedHistory = firstNodeValidators
       .flatMap(v => stats.stats[v.toString().toLowerCase()].history)
-      .filter(h => h.slot > initialSlot && h.slot <= slotForSentinel)
+      .filter(h => h.slot === slotForSentinel)
       .filter(h => h.status === 'checkpoint-valid' || h.status === 'checkpoint-mined');
     expect(firstNodeBlockProposedHistory).not.toBeEmpty();
 
-    // And all of the proposers for the offline node must be seen as missed attestation or proposal
+    // And all of the validators for the offline node must be seen as missed attestation or proposal.
     for (const validator of offlineValidators) {
-      const validatorStats = stats.stats[validator.toString().toLowerCase()];
-      const history = validatorStats.history?.filter(h => h.slot > initialSlot && h.slot <= slotForSentinel) ?? [];
+      const history = historyForSlot(validator);
       t.logger.info(`Asserting stats for offline validator ${validator}`, { history });
       expect(
         history.filter(