[fix:] one-line addresses were visible in pdf creation

Tasks/AddressCreation.cs

@@ -194,7 +194,8 @@ public static class AddressCreator
             string_address = names + "\n" + string_address;
         } // Error-Handling?
 
-        return string_address;
+        if (address_line_count > 1) return string_address;
+        return null;
     }
 
     public static string CreateNameLine(string anredezus, string anrede, string titel, string vorname, string adel,

Tasks/PdfBuilder.cs

@@ -73,7 +73,7 @@ public class PdfBuilder
         for (var i = 0; i < addressSet.KasPersons.Count; i++)
         {
             var addr = AddressCreator.CreateFinalMarkdownString(addressSet.KasPersons[i].refsid);
-            if (string.IsNullOrWhiteSpace(addr.Trim())) continue;
+            if (string.IsNullOrWhiteSpace(addr)) continue;
             if (!string.IsNullOrEmpty(senderLine))
                 addresses.Add(senderLine + (addr ?? ""));
             else