Update Messaging.md

[abunsen]

This is an attempt to clarify that React Native Firebase method: firebase.messaging().hasPermission() does not check with Firebase Cloud Messaging platform, but instead only checks the device permissions.

[CLAassistant]

All committers have signed the CLA.

[abunsen]

@Salakar @Ehesp would love to bring some clarity to this issue.

[SkarDude]

💯

I just did a POC supporting this claim and it is true

[mikehardy]

I have a question about this, I get the point - the messaging check is local, but...is "cloud messaging permission" a thing? I didn't there was the concept of permissions at all at the cloud level, just per device?

If I understand that correctly then the messaging shouldn't be as if there were two possibilities and this only checks one, it should instead clarify that permissions only exists on the device and you have to check it.

It's subtle, but I wouldn't want an attempt to clarify things make it seem as if there was some other permissions scheme out there

Or am I missing an FCM cloud messaging permissions thing?