Make clock picker view model aware of if edited

We check if the selected option is the same as the system one to see if
there are any changes. If yes, we will enable the on apply by emitting a
non null onApply function.

Test: Manually tested
Bug: 376092261
Flag: com.android.systemui.shared.new_customization_picker_ui
Change-Id: I07ad844f96501bd67a6816c202eaacc199ea3e9f