refactor: fix nullCoalesce.variable errors (#9524)

Author: warcooft

Diff for: system/HTTP/RedirectResponse.php

@@ -93,8 +93,8 @@ public function withInput()
     {
         $session = service('session');
         $session->setFlashdata('_ci_old_input', [
-            'get'  => $_GET ?? [],
-            'post' => $_POST ?? [],
+            'get'  => $_GET ?? [], // @phpstan-ignore nullCoalesce.variable
+            'post' => $_POST ?? [], // @phpstan-ignore nullCoalesce.variable
         ]);
 
         $this->withErrors();

Diff for: utils/phpstan-baseline/loader.neon

@@ -1,4 +1,4 @@
-# total 3541 errors
+# total 3539 errors
 includes:
     - argument.type.neon
     - assign.propertyType.neon
@@ -22,7 +22,6 @@ includes:
     - missingType.return.neon
     - notIdentical.alwaysTrue.neon
     - nullCoalesce.property.neon
-    - nullCoalesce.variable.neon
     - offsetAccess.notFound.neon
     - property.defaultValue.neon
     - property.nonObject.neon