Fix empty string comparison issues in the codebase (#16686)

Automatic Merge

model/group.go

@@ -139,7 +139,7 @@ func (group *Group) IsValidForCreate() *AppError {
 		return NewAppError("Group.IsValidForCreate", "model.group.source.app_error", nil, "", http.StatusBadRequest)
 	}
 
-	if len(group.RemoteId) > GroupRemoteIDMaxLength || (len(group.RemoteId) == 0 && group.requiresRemoteId()) {
+	if len(group.RemoteId) > GroupRemoteIDMaxLength || (group.RemoteId == "" && group.requiresRemoteId()) {
 		return NewAppError("Group.IsValidForCreate", "model.group.remote_id.app_error", nil, "", http.StatusBadRequest)
 	}