### Elasticsearch Version

main@b6747b48ba0901a530ba51375e3576fdb8df8527

### Installed Plugins

_No response_

### Java Version

openjdk version "17.0.8" 2023-07-18

### OS Version

Ubuntu 23.04

### Problem Description

`row a = 1 | stats max(1) by a` (or some other agg) results in:
```
Caused by: java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:233)
	at java.base/java.util.ImmutableCollections$List12.<init>(ImmutableCollections.java:556)
	at java.base/java.util.List.of(List.java:812)
	at org.elasticsearch.xpack.esql.planner.AbstractPhysicalOperationProviders.aggregatesToFactory(AbstractPhysicalOperationProviders.java:185)
	at org.elasticsearch.xpack.esql.planner.AbstractPhysicalOperationProviders.groupingPhysicalOperation(AbstractPhysicalOperationProviders.java:133)
	at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planAggregation(LocalExecutionPlanner.java:207)
	at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:158)
	at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planAggregation(LocalExecutionPlanner.java:207)
	at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:158)
	at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planLimit(LocalExecutionPlanner.java:520)
	at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:176)
	at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.planOutput(LocalExecutionPlanner.java:259)
	at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:198)
	at org.elasticsearch.xpack.esql.planner.LocalExecutionPlanner.plan(LocalExecutionPlanner.java:147)
	at org.elasticsearch.xpack.esql.plugin.ComputeService.runCompute(ComputeService.java:204)
	... 147 more
```

@nik9000 's thoughts on this: `I think this is just a kind of special case of "I can't EVAL in STATS". But it's a case the parser accepts.`

### Steps to Reproduce

Run the ESQL query from above.

### Logs (if relevant)

_No response_
x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/analysis/VerifierTests.java
error("from test | rename emp_no as r1, r1 as r2, emp_no as r3 | keep r3")
        );
    }
    public void testDuplicateRenaming() {
        assertEquals(
            "1:34: Column [emp_no] renamed to [r1] and is no longer available [emp_no as r1]",
            error("from test | rename emp_no as r1, emp_no as r1 | keep r1")
        );
    }
    public void testDoubleRenamingReference() {
        assertEquals(
            "1:61: Column [r1] renamed to [r2] and is no longer available [r1 as r3]",
            error("from test | rename emp_no as r1, r1 as r2, first_name as x, r1 as r3 | keep r3")
        );
    }
    public void testDropAfterRenaming() {
        assertEquals("1:40: Unknown column [emp_no]", error("from test | rename emp_no as r1 | drop emp_no"));
    }
    public void testNonStringFieldsInDissect() {
        assertEquals(
            "1:21: Dissect only supports KEYWORD or TEXT values, found expression [emp_no] type [INTEGER]",
            error("from test | dissect emp_no \"%{foo}\"")
        );
    }
    public void testNonStringFieldsInGrok() {
        assertEquals(
            "1:18: Grok only supports KEYWORD or TEXT values, found expression [emp_no] type [INTEGER]",
            error("from test | grok emp_no \"%{WORD:foo}\"")
        );
    }