minor #9756 [Config] Removed duplicated condition (gnugat)

This PR was submitted for the 2.4-dev branch but it was merged into the 2.4 branch instead (closes #9756).

Discussion
----------

[Config] Removed duplicated condition

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | none
| License       | MIT
| Doc PR        | none

Removed unnecessary condition (looks like it's been copy/pasted from
line 84).

Commits
-------

5c9dd30 [Config] Removed duplicated condition

src/Symfony/Component/Config/Definition/Dumper/YamlReferenceDumper.php

@@ -97,7 +97,7 @@ private function writeNode(NodeInterface $node, $depth = 0)
                 $default = $node->getDefaultValue();
 
                 if (is_array($default)) {
-                    if ($node->hasDefaultValue() && count($defaultArray = $node->getDefaultValue())) {
+                    if (count($defaultArray = $node->getDefaultValue())) {
                         $default = '';
                     } elseif (!is_array($example)) {
                         $default = '[]';