Adjusted permission check

[nmggithub]

Since late 2019, getToken() has automatically requested permission, so no need to check if it is granted here

Checklist

• Issue number for this PR: .getToken() method on AngularFireMessaging fails too early on notification mermission. #2762 (required)
• Docs included?: no (this is not a functional change that requires documentation, as it simply bring angularfire in line with the underlying library)
• Test units included?: no
• In a clean directory, yarn install, yarn test run successfully? yes

Description

As explained in the commit: since late 2019, getToken() has automatically requested permission, so no need to check if it is granted here.

[jamesdaniels]

The problem is AngularFire's API has always expected the developer to request permission manually, so in order to not break semver & take the peer we gated it. We can consider dropping this at the next major version, not before.

[nmggithub]

The problem is AngularFire's API has always expected the developer to request permission manually, so in order to not break semver & take the peer we gated it. We can consider dropping this at the next major version, not before.

Good to know. Looking forward to it.

[jamesdaniels]

Hey there, we have a new major of AngularFire coming up, but we've changed directions and are shipping the same API as Firebase JS SDK. Thanks for the contribution but I'm going to close this as it's no longer relevant to the new design #2770. Looking forward to any ideas you might have to improve the library in the future!