[framework-bundle/5.3] Merge per-env settings

Author: nicolas-grekas

symfony/framework-bundle/5.3/config/packages/framework.yaml

@@ -15,3 +15,9 @@ framework:
     #fragments: true
     php_errors:
         log: true
+
+when@test:
+    framework:
+        test: true
+        session:
+            storage_factory_id: session.storage.factory.mock_file

symfony/framework-bundle/5.3/config/packages/test/framework.yaml

@@ -0,0 +1,4 @@
+when@dev:
+    _errors:
+        resource: '@FrameworkBundle/Resources/config/routing/errors.xml'
+        prefix: /_error