Fenix: [Bug]New Tab FAB disappears after rotation

[AndiAJ]

Steps to reproduce

1. Open 2 tabs
2. Tap the tabs counter and open the tabs tray
3. Rotate the device to landscape view
4. Rotate the device back to portrait view

Expected behavior

The New Tab FAB should be available.

Actual behavior

The New Tab FAB disappears.
After rotating back the device to portrait view, the Tabs Tray seems to be moving
Also, the "Select tabs" button disappears for a couple of seconds.

Device information

• Android device:
  OnePlus A3 (Android 6.0.1)

• Fenix version:
  • Nightly 201120
  • Beta 84.0.0-beta.1

Notes

❗ Reproducible in both List view and Grid view

► Video

[ebalazs-sv]

Verified as fixed on Nightly 201214 05:03 (Build #2015781291) GV 85 from 12/14 with Samsung Galaxy Tab S3 (Android 8) and Pixel 2 (Android 9).
I will close the issue and remove the qa:needed label for now.