[Bug] Undo snackbar pushes FAB up in the new tab tray

[miDeb]

Steps to reproduce

• Open a new tab
• Close the tab

Expected behavior

The FAB stays at the same position

Actual behavior

The FAB is pushed up by the snackbar, the "undo" button is now at its position. This is counterintuitive, as opening a new tab is a very common action and users will build up muscle memory for tapping that button. Therefore, I believe that the FAB should always have a fixed position on screen.
Also, this violates the Material Design spec:

Don’t animate other components along with snackbar animations, such as the floating action button.

Device information

• Android device: Samsung Galaxy A50
• Fenix version: Nightly 200530 06:01

┆Issue is synchronized with this Jira Task

[astarq]

The snackbar is also a bit low down, my phone has curved corners and the snackbar is slightly hidden under them now
Device: Galaxy S8

[miDeb]

Fixed by #11930.