[irods/irods#8278] Remove documentation on msiSendMail

Author: MartinFlores751

docs/system_overview/configuration.md

@@ -56,11 +56,6 @@ This file defines the behavior of the server Agent that answers individual reque
             "cache_clearer_sleep_time_in_seconds": 600
         },
 
-        // (Optional)
-        // Controls whether invocation of the msiSendMail microservice is allowed on the server.
-        // This option is NOT included on new installations or added during upgrades.
-        "enable_deprecated_msiSendMail": false,
-
         // (Optional)
         // Contains settings for controlling the behavior of the internal Hostname cache.
         "hostname_cache": {