MM-25014 - Default Group Name to null, until AllowGroupReference is set (#14651)

* make Group.Name a pointer to allow null

* fix unit tests

* fix build error

* fix unit test

* ensure Name field not nil

Co-authored-by: mattermod <mattermod@users.noreply.github.com>

api4/ldap.go

@@ -194,11 +194,9 @@ func linkLdapGroup(c *Context, w http.ResponseWriter, r *http.Request) {
 	} else {
 		// Group has never been linked
 		//
-		// TODO: In a future phase of LDAP groups sync `Name` will be used for at-mentions and will be editable on
-		// the front-end so it will not have an initial value of `model.NewId()` but rather a slugified version of
-		// the LDAP group name with an appended duplicate-breaker.
+		// For group mentions implementation, the Name column will no longer be set by default.
+		// Instead it will be set and saved in the web app when Group Mentions is enabled.
 		newGroup := &model.Group{
-			Name:        model.NewId(),
 			DisplayName: displayName,
 			RemoteId:    ldapGroup.RemoteId,
 			Source:      model.GroupSourceLdap,