Revert of notifying suggestion space visible in UMO

Not able to figure out at the moment why there is a regression caused by
this change, despite this code path being flagged off. At this point it
seems safer to revert, and then to monitor whether the regression is
fixed.

Test: atest
Flag: com.android.systemui.enable_suggested_device_ui
Bug: 411049380
Change-Id: I8236cd3501d5c691a659d414d3c8626b44279011