Button: Background colour not animating to the selected colour.

[enejb]

Describe the bug
Currently when you have a background colour selected other then the custom background colour, If you go back into the colour selection, the UI doesn't scroll into to show what you have selected.

To Reproduce
Steps to reproduce the behavior:

1. Add a button block, got the settings of the block.
2. Choose the very last background colour before custom.
3. Exit the background colour selection.
4. Go back to change the background colour.
5. Notice that you have to scroll to the end to see the background colour that is currently selected.

Expected behavior
That when a background colour is selected that the the selection scroll the selection into view.

Smartphone (please complete the following information):

• Device: iPhone 11 Pro, Samsung A8
• OS: iOS 14, Android

[chipsnyder]

Related to #3104