Revert "better error msg"

This reverts commit 21ec77c.

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/parser/LogicalPlanBuilder.java

@@ -445,9 +445,7 @@ public PlanFactory visitEnrichCommand(EsqlBaseParser.EnrichCommandContext ctx) {
     public PlanFactory visitChangePointCommand(EsqlBaseParser.ChangePointCommandContext ctx) {
         Source src = source(ctx);
         NamedExpression value = visitQualifiedName(ctx.value);
-        NamedExpression key = ctx.key == null
-            ? new UnresolvedAttribute(src, "@timestamp", "Key column unspecified and default [@timestamp] is missing")
-            : visitQualifiedName(ctx.key);
+        NamedExpression key = ctx.key == null ? new UnresolvedAttribute(src, "@timestamp") : visitQualifiedName(ctx.key);
         Attribute targetType = new ReferenceAttribute(
             src,
             ctx.targetType == null ? "type" : visitQualifiedName(ctx.targetType).name(),

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/analysis/VerifierTests.java

@@ -2021,10 +2021,8 @@ public void testChangePoint() {
         var airports = AnalyzerTestUtils.analyzer(loadMapping("mapping-airports.json", "airports"));
         assertEquals("1:30: Unknown column [blahblah]", error("FROM airports | CHANGE_POINT blahblah ON scalerank", airports));
         assertEquals("1:43: Unknown column [blahblah]", error("FROM airports | CHANGE_POINT scalerank ON blahblah", airports));
-        assertEquals(
-            "1:17: Key column unspecified and default [@timestamp] is missing",
-            error("FROM airports | CHANGE_POINT scalerank", airports)
-        );
+        // TODO: nicer error message for missing default column "@timestamp"
+        assertEquals("1:17: Unknown column [@timestamp]", error("FROM airports | CHANGE_POINT scalerank", airports));
     }
 
     public void testChangePoint_keySortable() {