fix(email): Add missing period in sentence

The URL sentence in the config.yml was missing a period at the end. This commit introduces punctuation for better readability and clearer communication in the Author Curation Portal note.

src/backend/config.yml

@@ -97,7 +97,7 @@ emails:
                      <br/>
                      If you have started on the form, but not finished, you may resume your submission to complete the process.<br/>
                      <br/>
-                     You can view all your papers already in the ACKnowledge system on the <a href=https://acp.acknowledge.textpressolab.com>Author Curation Portal</a><br/>
+                     You can view all your papers already in the ACKnowledge system on the <a href=https://acp.acknowledge.textpressolab.com>Author Curation Portal</a>.<br/>
                      <br/>
                      If you have questions about completing the form, please feel free to reply to this email and we will be happy to assist<br/>
                      you. {}<br/>