ACQE-5377: [Stabilithon] Review and deliver submitted Pull Requests

 - deprecate AdminReindexAndFlushCacheActionGroup.xml

Author: okolesnyk

app/code/Magento/Indexer/Test/Mftf/ActionGroup/AdminReindexAndFlushCacheActionGroup.xml

@@ -7,7 +7,7 @@
 -->
 <actionGroups xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
               xsi:noNamespaceSchemaLocation="urn:magento:mftf:Test/etc/actionGroupSchema.xsd">
-    <actionGroup name="AdminReindexAndFlushCache">
+    <actionGroup name="AdminReindexAndFlushCache" deprecated="This AG is deprecated, please use (CliIndexerReindexActionGroup, CliCacheCleanActionGroup, CliCacheFlushActionGroup) instead">
         <annotations>
             <!--
                 PLEASE NOTE: