Bugfix: Notice: Undefined index: method thrown in SerializerContextBu… (#3128)

* Bugfix: Notice: Undefined index: method thrown in SerializerContextBuilder (since version 2.5.0)
- switch the order of the checks in the if statement to prevent checking for non-existent 'method' key in $operation check.

* Update src/Serializer/SerializerContextBuilder.php

Co-Authored-By: Kévin Dunglas <[email protected]>

Author: mhbert

src/Serializer/SerializerContextBuilder.php

@@ -94,7 +94,7 @@ public function createFromRequest(Request $request, bool $normalization, array $
         }
 
         foreach ($resourceMetadata->getItemOperations() as $operation) {
-            if ('PATCH' === $operation['method'] && \in_array('application/merge-patch+json', $operation['input_formats']['json'] ?? [], true)) {
+            if ('PATCH' === ($operation['method'] ?? '') && \in_array('application/merge-patch+json', $operation['input_formats']['json'] ?? [], true)) {
                 $context['skip_null_values'] = true;
 
                 break;