Revert "MQE-2462 updated the creds file"

This reverts commit 33a0230.

Author: mahesh-singh-rajawat

app/code/Magento/Backend/Test/Mftf/ActionGroup/AdminLoginActionGroup.xml

@@ -13,8 +13,8 @@
             <description>Login to Backend Admin using provided User Data. PLEASE NOTE: This Action Group does NOT validate that you are Logged In.</description>
         </annotations>
         <arguments>
-            <argument name="username" type="string" defaultValue="{{_CREDS.magento/MAGENTO_ADMIN_USERNAME}}"/>
-            <argument name="password" type="string" defaultValue="{{_CREDS.magento/MAGENTO_ADMIN_PASSWORD}}"/>
+            <argument name="username" type="string" defaultValue="{{_ENV.MAGENTO_ADMIN_USERNAME}}"/>
+            <argument name="password" type="string" defaultValue="{{_ENV.MAGENTO_ADMIN_PASSWORD}}"/>
         </arguments>
 
         <amOnPage url="{{AdminLoginPage.url}}" stepKey="navigateToAdmin"/>