imp - Fetch the last dot for property grouping

---

We need to get the last dot from the prefix when parsing grouped properties.

---

Type: imp
Breaking: False
Doc Required: False
Backport Required: False
Part: 1/1

VisualCard.ShowContacts/TestFiles/VCard4GroupProps.vcf

@@ -2,16 +2,16 @@ BEGIN:VCARD
 VERSION:4.0
 UID:urn:uuid:136c1090-d7d3-4399-9f59-8f7a7b6e2ef1
 ADR;TYPE=home:;;New York\, USA;;;;
-A.EMAIL;TYPE=HOME:[email protected]
-B.EMAIL;TYPE=WORK:[email protected]
+E.A.EMAIL;TYPE=HOME:[email protected]
+E.B.EMAIL;TYPE=WORK:[email protected]
 FN:Sarah Santos
 N:Santos;Sarah;;;
 ORG:Support Scammer Outcry Organization
-A.TEL;TYPE=cell:589-210-1059
-B.TEL;TYPE=cell:589-210-1058
+T.A.TEL;TYPE=cell:589-210-1059
+T.B.TEL;TYPE=cell:589-210-1058
 TITLE:Chief Executive Officer
-URL:https://sso.org/
-X-SIP-SIP:sip test
+S.URL:https://sso.org/
+S.X-SIP-SIP:sip test
 ANNIVERSARY:20230406
 GENDER:F;grrrl
 DRESSCODE:CASUAL

VisualCard.ShowContacts/TestFiles/fourVCard4.vcf

@@ -13,7 +13,7 @@ ADR;TYPE=home:;;Street Address;;;;
 EMAIL;TYPE=HOME:[email protected]
 EMAIL;TYPE=WORK:[email protected]
 FN:Neville Navasquillo
-A.IMPP;TYPE=HOME:aim:IM
+IMPP;TYPE=HOME:aim:IM
 IMPP;TYPE=HOME:msn:Windows LIVE
 IMPP;TYPE=HOME:ymsgr:Yahoo
 N;ALTID=0;LANGUAGE=en:Navasquillo;Neville;Neville\,Nevile;Mr.;Jr.

VisualCard/Parsers/Arguments/PropertyInfo.cs

@@ -50,7 +50,7 @@ public class PropertyInfo : IEquatable<PropertyInfo?>
             prefix;
 
         /// <summary>
-        /// Property group
+        /// Property group (dots are for nested groups)
         /// </summary>
         public string Group =>
             group;
@@ -125,7 +125,7 @@ internal PropertyInfo(string line)
             var finalArgs = splitArgs.Select((arg) => new ArgumentInfo(arg)).ToArray();
 
             // Extract the group name
-            string group = prefix.Contains(".") ? prefix.Substring(0, prefix.IndexOf(".")) : "";
+            string group = prefix.Contains(".") ? prefix.Substring(0, prefix.LastIndexOf(".")) : "";
             prefix = prefix.RemovePrefix($"{group}.");
 
             // Check to see if this is a nonstandard prefix