ACP2E-1512: Env variable config not working for store views with capital letters in the code

covered env setting issue

Author: aplapana

app/code/Magento/Store/Model/Config/Processor/Fallback.php

@@ -111,6 +111,13 @@ private function prepareWebsitesConfig(
         array $websitesConfig
     ) {
         $result = [];
+
+        foreach ($websitesConfig as $websiteCode => $webConfiguration) {
+            if (!isset($websitesConfig[strtolower($websiteCode)])) {
+                $websitesConfig[strtolower($websiteCode)] = $webConfiguration;
+                unset($websitesConfig[$websiteCode]);
+            }
+        }
         foreach ((array)$this->websiteData as $website) {
             $code = $website['code'];
             $id = $website['website_id'];
@@ -136,6 +143,12 @@ private function prepareStoresConfig(
     ) {
         $result = [];
 
+        foreach ($storesConfig as $storeCode => $storeConfiguration) {
+            if (!isset($storesConfig[strtolower($storeCode)])) {
+                $storesConfig[strtolower($storeCode)] = $storeConfiguration;
+                unset($storesConfig[$storeCode]);
+            }
+        }
         foreach ((array)$this->storeData as $store) {
             $code = $store['code'];
             $id = $store['store_id'];

app/code/Magento/Store/Test/Unit/Model/Config/Processor/FallbackTest.php

@@ -78,7 +78,7 @@ public function testProcessWithStoreCodeCapitalLetters()
         $result = $this->fallback->process(
             [
                 'stores' => [
-                    'two' => [
+                    'TWO' => [
                         'checkout' => [
                             'options' => ['guest_checkout' => 0]
                         ]