Accommodate Firebase App data streams

[alphanumerritt]

• page_view is screen_view for apps
• Many common event parameters have different names (e.g. page_location = screen_class)
• Boolean values show as strings in web data streams but as integers in apps
• Traffic source data comes in a dedicated event firebase_campaign and is not available on session_start event

[DavidBachNZME]

I'm keen to see how this has been handled as we're setting up this GA4 model currently across app and web properties. We'd like to have a common key across page and screen views, but for app there is no page location which forms the page key (id)

[dgitis]

It is possible that I get a client project to integrate mobile in which case I'll definitely take that up.

That project seems to be moving quite slowly right now, though. If either of you can't wait, then feel free to go ahead and start working on it. I'd be happy to chime in and help if you get stuck on anything.