bug #3951 Don't override the query_builder form option in associations (javiereguiluz)

This PR was merged into the 3.0.x-dev branch.

Discussion
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Don't override the query_builder form option in associations

This is related to #3551, which we merged yesterday. One of my apps started failing because it used a custom `query_builder` form option.

Commits
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3cc9c8a Don't override the query_builder form option in associations

Author: javiereguiluz

src/Field/Configurator/AssociationConfigurator.php

@@ -81,7 +81,7 @@ public function configure(FieldDto $field, EntityDto $entityDto, AdminContext $c
 
             $field->setFormTypeOption('attr.data-ea-autocomplete-endpoint-url', $autocompleteEndpointUrl);
         } else {
-            $field->setFormTypeOption('query_builder', static function (EntityRepository $repository) use ($field) {
+            $field->setFormTypeOptionIfNotSet('query_builder', static function (EntityRepository $repository) use ($field) {
                 // TODO: should this use `createIndexQueryBuilder` instead, so we get the default ordering etc.?
                 // it would then be identical to the one used in autocomplete action, but it is a bit complex getting it in here
                 $queryBuilder = $repository->createQueryBuilder('entity');