Do not cache SingleValueQuery.LuceneQuery (elastic#110082)

If the query gets cached, then it won't be able to emit warnings for multivalue fields.

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/querydsl/query/SingleValueQuery.java

@@ -452,7 +452,8 @@ private Scorer scorer(Scorer nextScorer, LeafFieldData lfd) {
 
         @Override
         public boolean isCacheable(LeafReaderContext ctx) {
-            return next.isCacheable(ctx);
+            // we cannot cache this query because we loose the ability of emitting warnings
+            return false;
         }
     }