fix(messaging, ios): force token to refresh when calling deleteToken

[helenaford]

Description

This will always refresh the fcm token, but it's unclear to me if this is the correct approach or not based on the documentation and changelog

I've opened up a ticket on firebase/firebase-ios-sdk#8491 for guidance from the iOS team.

I don't believe there are any side-effects of always deleting the installations id, but it would be good to get confirmation as this approach always will delete it when refreshing the fcm token.

Related Issues

Fixes #6766

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