### Problem Description

```
Caused by: java.lang.NullPointerException: Cannot invoke "java.lang.Integer.intValue()" because the return value of "org.elasticsearch.xpack.esql.planner.Layout.getChannel(org.elasticsearch.xpack.ql.expression.NameId)" is null
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planProject(LocalExecutionPlanner.java:521)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:174)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planExchangeSink(LocalExecutionPlanner.java:304)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:202)
        at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:149)
        at org.elasticsearch.xpack.esql.plugin.ComputeService.runCompute(ComputeService.java:252)
        at org.elasticsearch.xpack.esql.plugin.ComputeService$DataNodeRequestHandler.lambda$messageReceived$5(ComputeService.java:422)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.action.ActionListener$2.onResponse(ActionListener.java:177)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.action.ActionListener.completeWith(ActionListener.java:305)
        at org.elasticsearch.xpack.esql.plugin.ComputeService.lambda$acquireSearchContexts$13(ComputeService.java:291)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.index.shard.IndexShard.ensureShardSearchActive(IndexShard.java:3926)
        at org.elasticsearch.xpack.esql.plugin.ComputeService.acquireSearchContexts(ComputeService.java:289)
        at org.elasticsearch.xpack.esql.plugin.ComputeService$DataNodeRequestHandler.messageReceived(ComputeService.java:420)
        at org.elasticsearch.xpack.esql.plugin.ComputeService$DataNodeRequestHandler.messageReceived(ComputeService.java:412)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.transport.RequestHandlerRegistry.processMessageReceived(RequestHandlerRegistry.java:75)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.transport.TransportService$6.doRun(TransportService.java:1019)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:983)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:26)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.common.util.concurrent.TimedRunnable.doRun(TimedRunnable.java:33)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:983)
        at org.elasticsearch.server@8.11.0-SNAPSHOT/org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:26)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
        at java.base/java.lang.Thread.run(Thread.java:1623)
```

### Steps to Reproduce

A very specific query (all commands must be used in that specific order) generates this NPE

```
from employees | limit 10 | rename first_name as somethingElse | stats var0 = avg(salary)
```

### Logs (if relevant)

_No response_
x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/optimizer/PhysicalPlanOptimizerTests.java
public void testProjectAfterTopN() throws Exception {
        var optimized = optimizedPlan(physicalPlan("""
            from test
            | sort emp_no
            | keep first_name
            | limit 2
            """));
        var topProject = as(optimized, ProjectExec.class);
        assertEquals(1, topProject.projections().size());
        assertEquals("first_name", topProject.projections().get(0).name());
        var topN = as(topProject.child(), TopNExec.class);
        var exchange = asRemoteExchange(topN.child());
        var project = as(exchange.child(), ProjectExec.class);
        List<String> projectionNames = project.projections().stream().map(NamedExpression::name).collect(Collectors.toList());
        assertTrue(projectionNames.containsAll(List.of("first_name", "emp_no")));
        var extract = as(project.child(), FieldExtractExec.class);
        var source = source(extract.child());
        assertThat(source.limit(), is(topN.limit()));
        assertThat(source.sorts(), is(sorts(topN.order())));
        
        assertThat(source.estimatedRowSize(), equalTo(Integer.BYTES * 5 + KEYWORD_EST));
    }
    /**
     * Expected
     *
     * EvalExec[[emp_no{f}#248 * 10[INTEGER] AS emp_no_10]]
     * \_LimitExec[10[INTEGER]]
     *   \_ExchangeExec[]
     *     \_ProjectExec[[_meta_field{f}#247, emp_no{f}#248, first_name{f}#249, languages{f}#250, last_name{f}#251, salary{f}#252]]
     *       \_FieldExtractExec[_meta_field{f}#247, emp_no{f}#248, first_name{f}#24..]