Improve mapRelatives in BaseObject

[alexsoft]

@irazasyed mapRelatives doesn't really supports initializing inner properties
So for example we get webhook update. Message is transformed to object of Message class, but 'from' and 'chat' fields are not.
This code fixes it. I am not sure if you need that continue, but second if does all the job.

[irazasyed]

Hi @alexsoft,

Thanks for opening the PR.

The way mapRelatives works is basically, the inner properties are initialized on-demand. I don't see any point in initializing all the inner properties and mapping them when you don't even need it.

Here's an example of how it would work with a webhook setup:

$update = Telegram::getWebhookUpdates();
$message = $update->getMessage(); // Maps to Message Object
$from = $message->getFrom(); // Maps to User Object
$chat = $message->getChat(); // Maps to Chat Object

Edit: For webhook this is definitely a good improvement and can be considered applying, But for manual fetching with maybe a good chunk of backlog messages, I'm concerned about its performance. Let me test this and I'll merge soon. Thanks!

[irazasyed]

I tested and it's not much of a difference but the improvement is still good. I noticed we could also use get() method from the collection API and still have the object properly mapped. Thanks!