Merge forwardport of magento/magento2#12758 to 2.3-develop branch

Applied pull request patch https://github.com/magento/magento2/pull/12758.patch (created by @Mobecls) based on commit(s):
  1. 937b26d
  2. 85fa671

Fixed GitHub Issues in 2.3-develop branch:
  - magento/magento2#5035: I can not to subscribe on change of all sections in Stores ->Configuration using event admin_system_config_changed_section (reported by @katesuykovskaya)

Author: magento-engcom-team

lib/internal/Magento/Framework/Event/Test/Unit/Config/_files/valid_events.xml

@@ -12,4 +12,7 @@
     <event name="authorization_roles_save_before">
         <observer name="second_name" instance="Some_Test_Value_Two" />
     </event>
+    <event name="authorization_roles_save_before123">
+        <observer name="second_name" instance="Some_Test_Value_Two"/>
+    </event>
 </config>