ESQL: Fix AggregatorFunctionSupplierImplementer warnings import (#121654)

Extracted from https://github.com/elastic/elasticsearch/pull/116170/files#diff-d8dcb5e856b601ac28b3dc0055e09d5c815d2577705eade446bd55b2fca42ac7R145

Those warnings are not being used in main yet, so there's no error, and that code wasn't being executed. But it better be fixed in main already

Author: ivancea

x-pack/plugin/esql/compute/gen/src/main/java/org/elasticsearch/compute/gen/AggregatorFunctionSupplierImplementer.java

@@ -33,6 +33,7 @@
 import static org.elasticsearch.compute.gen.Types.DRIVER_CONTEXT;
 import static org.elasticsearch.compute.gen.Types.LIST_INTEGER;
 import static org.elasticsearch.compute.gen.Types.STRING;
+import static org.elasticsearch.compute.gen.Types.WARNINGS;
 
 /**
  * Implements "AggregationFunctionSupplier" from a class annotated with both
@@ -139,8 +140,9 @@ private MethodSpec aggregator() {
 
         if (hasWarnings) {
             builder.addStatement(
-                "var warnings = Warnings.createWarnings(driverContext.warningsMode(), "
-                    + "warningsLineNumber, warningsColumnNumber, warningsSourceText)"
+                "var warnings = $T.createWarnings(driverContext.warningsMode(), "
+                    + "warningsLineNumber, warningsColumnNumber, warningsSourceText)",
+                WARNINGS
             );
         }
 
@@ -164,8 +166,9 @@ private MethodSpec groupingAggregator() {
 
         if (hasWarnings) {
             builder.addStatement(
-                "var warnings = Warnings.createWarnings(driverContext.warningsMode(), "
-                    + "warningsLineNumber, warningsColumnNumber, warningsSourceText)"
+                "var warnings = $T.createWarnings(driverContext.warningsMode(), "
+                    + "warningsLineNumber, warningsColumnNumber, warningsSourceText)",
+                WARNINGS
             );
         }