public void RequireUserIsGroupMemberFromChat(string username, Guid chatId)
{
var user = _userValidationService.RequireAndGetUserByUsername(username);
var chat = RequireAndGetChatById(chatId);
_groupValidationService.RequireUserIdIsGroupMember(
user.Id,
chat.GroupId,
"User is not a member of group, to which this chat belongs."
);
}
