### 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
assertThat(tq.fieldName(), is("_index"));
        assertThat(tq.value(), is("test"));
    }
    /*
     * LimitExec[10000[INTEGER]]
     * \_ExchangeExec[[],false]
     *   \_ProjectExec[[_meta_field{f}#9, emp_no{f}#3, first_name{f}#4, gender{f}#5, languages{f}#6, last_name{f}#7, salary{f}#8, _in
     *     dex{m}#1]]
     *     \_FieldExtractExec[_meta_field{f}#9, emp_no{f}#3, first_name{f}#4, gen..]
     *       \_LimitExec[10000[INTEGER]]
     *         \_FilterExec[_index{m}#1 > [74 65 73 74][KEYWORD]]
     *           \_FieldExtractExec[_index{m}#1]
     *             \_EsQueryExec[test], query[][_doc{f}#10], limit[], sort[] estimatedRowSize[266]
     */
    public void testDontPushDownMetadataIndexInInequality() {
        for (var t : List.of(
            tuple(">", GreaterThan.class),
            tuple(">=", GreaterThanOrEqual.class),
            tuple("<", LessThan.class),
            tuple("<=", LessThanOrEqual.class)
            
        )) {
            var plan = physicalPlan("from test [metadata _index] | where _index " + t.v1() + " \"test\"");
            var optimized = optimizedPlan(plan);
            var limit = as(optimized, LimitExec.class);
            var exchange = asRemoteExchange(limit.child());
            var project = as(exchange.child(), ProjectExec.class);
            var extract = as(project.child(), FieldExtractExec.class);
            limit = as(extract.child(), LimitExec.class);
            var filter = as(limit.child(), FilterExec.class);