Site Icon: Add 192x192 site for Android devices

[kraftbj]

Android uses 192x192 for home screen tiles and for favicons used when using the application switcher to change Chrome tabs.

Currently, if a 192x192 size is not provided, it falls back to Apple icon meta; however, this is deprecated and noted to be removed in a future version (​https://developer.chrome.com/multidevice/android/installtohomescreen#icon)

See #16434 (master ticket)

Adds 192 in the size array and outputs it.

Patch needs to be updated to take into account the unit tests that we now have for site_icon

32964.patch plus unit tests.

32964.2.patch amends the unit tests to account for a new default size. Ran phpunit on a fresh copy of trunk, then with 32964.patch, then again with .2 to confirm that the original patch invalidated the tests and the .2 resolved.

12px. ಠ_ಠ

If we can get all cell phone makers to use the same power connection (Apple being the hold out on this go round), then we can ask them to please just agree on something together :)

In 33202:

Site Icon: Add Android-specific app icon.

Falling back to Apple app icons is deprecated behavior and will not work
forever. 192px is the recommended size for that icon.

Props kraftbj.
Fixes #32964.