ENGCOM-8370: checkout_index_index.xml file code improvement. #30538

 - Merge Pull Request #30538 from sanganinamrata/magento2:hacktoberfest_pr_3
 - Merged commits:
   1. 9372950

Author: magento-engcom-team

app/code/Magento/Checkout/view/frontend/layout/checkout_index_index.xml

@@ -32,12 +32,10 @@
                                 </item>
                                 <item name="children" xsi:type="array">
                                     <item name="errors" xsi:type="array">
-                                        <item name="sortOrder" xsi:type="string">0</item>
                                         <item name="component" xsi:type="string">Magento_Ui/js/view/messages</item>
                                         <item name="displayArea" xsi:type="string">messages</item>
                                     </item>
                                     <item name="authentication" xsi:type="array">
-                                        <item name="sortOrder" xsi:type="string">1</item>
                                         <item name="component" xsi:type="string">Magento_Checkout/js/view/authentication</item>
                                         <item name="displayArea" xsi:type="string">authentication</item>
                                         <item name="children" xsi:type="array">
@@ -50,7 +48,6 @@
                                         </item>
                                     </item>
                                     <item name="progressBar" xsi:type="array">
-                                        <item name="sortOrder" xsi:type="string">0</item>
                                         <item name="component" xsi:type="string">Magento_Checkout/js/view/progress-bar</item>
                                         <item name="displayArea" xsi:type="string">progressBar</item>
                                         <item name="config" xsi:type="array">
@@ -61,7 +58,6 @@
                                         </item>
                                     </item>
                                     <item name="estimation" xsi:type="array">
-                                        <item name="sortOrder" xsi:type="string">10</item>
                                         <item name="component" xsi:type="string">Magento_Checkout/js/view/estimation</item>
                                         <item name="displayArea" xsi:type="string">estimation</item>
                                         <item name="config" xsi:type="array">
@@ -335,7 +331,6 @@
                                         </item>
                                     </item>
                                     <item name="sidebar" xsi:type="array">
-                                        <item name="sortOrder" xsi:type="string">50</item>
                                         <item name="component" xsi:type="string">Magento_Checkout/js/view/sidebar</item>
                                         <item name="displayArea" xsi:type="string">sidebar</item>
                                         <item name="config" xsi:type="array">