Refactor SearchScreen

[rafsanjani]

You can improve SearchScreen by applying the following;

• Do not pass the ViewModel object down to its children. Instead, extract the data you need from the ViewModel and pass those data along.
• Make all other functions in SearchScreen private to prevent namespace pollution.
• ObserveCurrentTime is quite misleading because it does more than just time observation. It also emits UI components.
• You are exposing Mutable data types from your ViewModel to the public. Normally, you would want your ViewModel to only expose states to the UI. The sequence of UI->VM usually goes along these lines;
  UI: Observes state from the VM
  UI: Invokes a function from the VM
  VM: Performs an operation
  VM: Updates a state internally and publishes to subscribers
  UI: Receives new state updates and refreshes components accordingly.