Deep links should open to the same site that was open in the browser

Expected behavior

I expect that if I tap on a deep link in my device web browser (sending me from the browser to the WP app) it will open the same site in the app as I was viewing in the browser.

Actual behavior

If I have multiple sites, and I have Site A selected in my web browser and Site B selected in the app, when I tap on a deep link for Stats or the Editor in Site A in the browser it sends me to Stats or the Editor for Site B in the app.

This is potentially confusing for stats, but much higher risk for the editor, where I might publish a post to the wrong site.

Steps to reproduce the behavior

1. Check what site is currently selected in the WordPress app.
2. In a web browser, go to WordPress.com and select a different site.
3. Go to My Sites > Stats in the web browser.
4. Tap the app banner ("Open in app").

Result: The app opens to the stats section for the wrong site.

Tested on Moto e5 Play, Android 8.1.1, WPAndroid alpha-135

cc @kwonye

Start by reproducing the Android deep-link flow from WordPress.com’s “Open in app” banner using two sites, then trace how the incoming Stats or Editor link is resolved against the currently selected site. Done means links from Site A open Stats or Editor for Site A even when Site B is selected in the app.