[FR] add firebase analytics event log to the sdk

**Is your feature request related to a problem? Please describe.**
I use firebase realtime database and firebase functions to realize most of my backend processing for my apps.
Currently firebase functions/firebase-admin-node is not able to register analytics events... this leads to several not optimal situation which i will relate one here.

When a user purchase something from my app, i use firebase functions + third party apis to process the payment and update the relevant data into the database... however this process might be asynchronous because many payments methods behave like this...
So, many times, right after the user purchase, i return the status 'pending' to the user and waiting the payment follow its flow.

When i get the final answer from the payment APIs, case the order is approved i would like to register a firebase analytics event so i can monitore such events on my firebase dashboard, but even there is a standard event for such situation, firebase functions is not able to register any analytics events because such api was designed to be used only by client applications.

so in this scenario i need to publish this into a topic, subscribe the client to the topic and write the event log in the client aplication.

**Describe the solution you'd like**
I know firebase analytics is designed to be client side because you collect many data for every event such as location, gender, age etc that only the client has... but there isn't any real tecnological limitation to avoid using it from backend ignoring the missing data.

If I the "business owner" dont care about demographic or geografical data about my purchases and only need to monitore its progress i wish i could simple register the event from firebase functions