[fenix] Remove tab tray feature flag (https://github.com/mozilla-mobile/fenix/pull/11176)
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Removes feature flag for the new tab tray
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Removes all tab references from homeFragment
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes unit tests
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Gets UI tests to compile and HomeScreenTest to pass
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes `deleteMultipleSelectionTest`
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes `openHistoryItemInNewPrivateTabTest`
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes `openHistoryInPrivateTabTest`
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes `openHistoryInNewTabTest`
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes `openNewPrivateTabTest`
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes tabbedBrowsingTests
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes SettingsPrivacyTest
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes TopSitesTest
* For https://github.com/mozilla-mobile/fenix/issues/11171 - Fixes lint errors
* Ignore