Adds configuration for separate reply-to email header. (#10144)

* Adds configuration for separate reply-to email header.

* Changes config setting name.

* Using a separate variable and value in test.

* Updates for config pointer changes in another PR.

* Adds new key to test config. Adds default value.

tests/test-config.json

@@ -163,6 +163,7 @@
         "RequireEmailVerification": false,
         "FeedbackName": "",
         "FeedbackEmail": "test@example.com",
+        "ReplyToAddress": "test@example.com",
         "FeedbackOrganization": "",
         "EnableSMTPAuth": false,
         "SMTPUsername": "",