[Bug] Tabs can't be saved in Collections

[ghost]

Steps to reproduce

1. Open tab
2. Save to Collection
3. Add new collection
   1. Expected behavior

• When you save a tab to the collection, it should be shown in Home Page of Fenix aka Collections

Actual behavior

• You open a tab, and you want to save it in your Collections, you click Preferences and on the opened tab and click Save to Collection you add a Collection or you save it on existing Collection. When you check for Collections, there will be none.

Device information

• Android device: Huawei P20 Lite / Android Version 8.0
• Fenix version: ?

┆Issue is synchronized with this Jira Task

[ekager]

This feature isn't implemented yet see #1575

[boek]

Added that menu item to the feature flag in #2535