Removed the new picker ui flag

Removed the picker ui flag since we created a new one under
systemui.shared so that the Launcher can also use the flag.

Test: Build success
Bug: 339081035
Flag: com.android.systemui.shared.new_customization_picker_ui
Change-Id: I969cc2689864aef0de4a5c4de096877d842bcc69
4 files changed